Category Archives: Mammals

Red Squirrel – Tamiasciurus hudsonicus Information

December 28, 2013 traderscreek

General: The Red Squirrel (Tamiasciurus hudsonicus) may be distinguished by its small size The red squirrel is most active in the early morning and its extreme territorial behavior, relative to other species of squirrels. Classified by the IUCN Red List as Least Concern, this widespread species is a common staple in ecosystems across North America. Spending its time hoarding massive amounts of cones and seeds for cold winter months, these squirrels are territorial of their nests and stockpiles and play an important role in seed distribution in their forest habitats.

Description: The Red Squirrel may be identified from other squirrels by their color, territorial behavior, and small size. Male and female squirrels are of a similar size and coloration, although regional variations can include color and size differences. The dorsal coloration can range from dark reddish brown, to brown or reddish-grey, contrasted by white or cream undersides. Unique markings include dark lateral lines on the body (which turn nearly black in the summer, separating the light underside from the dark upper,) white eye- rings, and tufted ears (evident during the winter.) The tail, flatter and 30% smaller than that of gray squirrels, may be yellowish-grey or deep red, with white or yellow tips on the hair and banded by black the length of the entire tail. Red Squirrels may weigh 197 to 282 grams, and be 6.5” to 9” long less than half the size of a fox squirrel. The tail makes up most of the body length, ranging from 3.5” to 6.5” in length. The Red Squirrel molts twice a year, once in the spring (between March and August, starting at the nose and ending at the posterior,) and once in the fall between August and December (starting at the tail and ending at the front legs)1. The tail of the Red Squirrel only molts in the fall. The body of the Red Squirrel is suited for climbing, with powerful rear legs and curved front claws used to grip bark.

In the wild, the Red Squirrel may live up to ten years; however, fewer than 25% of Red Squirrels live past the first year. The average lifespan of the Red Squirrel is three to seven years2 in the wild and five years in captivity.

The Red Squirrel has highly developed senses of smell, hearing and sight, making them well suited for foraging, climbing, and alluding predators.

Health: Red Squirrels are susceptible to a number of physical ailments, including parasites, fungal diseases, and viruses. Endoparasites (internal) include nematodes, tapeworms, tularemia bacteria, and sarocysts. Ectoparasties (external) include mites, ticks, fleas, and botfly larvae. They may develop a fungal lung disease infection by hosting adiaspiromycosis3. They are also prone to a number of viruses, including the silverwater virus, California encephalitis virus and Powassan virus4.

Behavior: Red Squirrels are a primarily diurnal species, most active during the early morning and in the late afternoon. During the fall red squirrels are generally more active in preparation of the winter.

During the winter, squirrels take advantage of mid-day temperature spikes, using this time to forage. These squirrels do not hibernate, despite common belief. Instead, they slow their activity levels according to temperatures. During the winter it is uncommon for a squirrel to stay inside a nest for more than one day without leaving to search for food. As temperatures dip below freezing, Red Squirrels become relatively inactive, taking refuge in a tree cavity, underground, or in a loosely constructed nest in a tree5.

The Red Squirrel is one of the most territorial squirrels of North America, using a variety of noises to defend their territory and food or fend off threats from predators. They are also very agile making them difficult to capture, but if cornered, they will defend themselves6. The Red Squirrel is known for its communication abilities, with noises ranging from rattles, chirps, screeches, and growls, to buzzes7. During mating season, males will use low aggressive, territorial calls to fend off other males. In response to threats, squirrels will give-off specific calls depending on the type of predator, a high frequency call for aerial attackers, or a sharp, bark for predators on the ground8.

In addition to vocal communication, Red Squirrels also use scent marking to aid in protection of territory or defense from predators, including snakes, birds of prey, and a variety of mammals9.

Habitat: Red Squirrels are primarily an arboreal species, inhabiting boreal coniferous, deciduous, or mixed northern forests. They may also reside in temperate or polar environments, in second-growth forests, suburban or urban areas, assuming coniferous trees are present with interlocking canopies and fungal resources10. Red Squirrels are found in a variety of ecosystems, with some populations living in mountainous regions up to 2500’. Territories, on average, are 2400 to 48000 square meters and are fiercely defended11.

Location: The Red Squirrel can be found across North America, with populations widely spread in Canada, Alaska, and parts of the United States, including the Rocky and Appalachian Mountains, and the Eastern United States as far south as northern Georgia12. 25 subspecies of the Red Squirrel have been identified. Isolated populations of the Red Squirrel include a subspecies in Arizona’s Pinaleño Mountains and an introduced population on the island of Newfoundland13.

Diet: Because the Red Squirrel inhabits areas with resource pulse systems (habitats with extreme seasonal variation in food supplies)14, they are opportunistic feeders who have been known to migrate in search of sustenance. These squirrels are primarily granivorous15, consuming a diet consisting mainly of conifer cones and seeds, and nuts. Their diets also include fruit, flowers, fungi, and buds, and when food supplies are low, will expand to include insects, bird eggs and hatchlings, and small vertebrates such as mice. Red Squirrels have also been observed feeding on sap, bark, and underlying tree tissue16.
Red Squirrels systematically harvest cones and seeds from pine trees and other conifers, collecting those with the highest energy density per cone first. The cones and seeds are cut from trees and stored in huge stockpiles, called middens. These food stores contain, on average, 2,000 to 4,000 cones and can be found in hollow stumps, at the bases of trees, underground, or under logs. Middens may contain upwards of 18,000 cones and be used by several generations of squirrels17. A typical sized midden holds enough food to last at least one or two seasons. Red Squirrels have also been known to use a process called scatter hoarding, hiding several small stockpiles of food rather than one large midden18. Because of their tendency to scatter food stores, Red Squirrels play an important part in seed distribution in their habitats.

Reproduction: Red Squirrels reach sexual maturity in one year and typically breed annually, following the cyclical production of conifer seeds and cones19. The breeding season lasts about 100 days, occurring in the spring. In warmer climates a second breeding season may occur in the late summer or early fall. Regional distribution causes variations in breeding times. For example, a second breeding season is common in the eastern United States, occurring in late July. Red Squirrels tend to be characterized as promiscuous in their mating but mating pairs do exist. Because of this behavior, an estrus female (in her period of ovulation) will be pursued by and mate with several males, participating in mating chases that can last up to several hours20. The dominant male will fend off the other males in the chase with physical displays of dominance or through audible communication. Estrus only lasts one day during the breeding season,21 and females will initiate copulation, which will occur several times during that afternoon. Gestation lasts, on average, 35 days. Litters may contain 1 to 8 offspring weighing just over 7 grams each22. The young are born naked and are weaned by 8 weeks old, although lactation occurs for 70 days23. By 18 weeks old the young are independent, moving away to establish their own territories. Sometimes, the mother will allot some or all of her territory to one or more of her young, moving away herself to establish a new territory. This act increases the success rate of her young.

Nests may be built in a number of locations, including tree hollows, cavities in the ground, in fallen logs or in tree limb junctions, although Red Squirrels prefer natural cavities. Nests are located within 100’ of food storage and are constructed of leaves, grass, moss, feathers, fur, or bark, depending on geographic location and available materials. When constructed in a tree, nests can be built from 6’ to 60’ off the ground.

Notes of Interest

Alternate names for the Red Squirrel include the North American Red Squirrel, Pine Squirrel, chickaree, and the Mount Graham Red Squirrel24.

The Mount Graham Red Squirrel is an isolated subspecies of the Red Squirrel consisting of one small population of approximately 250 squirrels. This subspecies was thought to be extinct in the 1950’s, but was rediscovered in the 1970’s25. This subspecies is endangered, according to the U.S. Fish and Wildlife Service.

The Red Squirrel faces a number of threats and certain populations and subspecies have experienced a decline in numbers due to harvesting for fur (the Red Squirrel is the third most harvested furbearer in Canada,) fragmentation of habitats due to forestry, construction of roads and civic development, forest fires, drought, and invasive species26.

Red Squirrels are a destructive species and may affect tree species as well as property. By stripping the bark and removing cones and buds from trees, these squirrels may inhibit the healthy growth of individual trees and tree populations. It has been determined that this species consumes 60% to 100% of cone crops in certain locations27. However, they also contribute to the distribution of seeds, leaving neglected stockpiles to germinate. Squirrels may also cause damage to property by nesting in homes or gnawing on items.

Red Squirrels have been known to bite humans when provoked28.

Footnotes

http://www.arkive.org/american-red-squirrel/tamiasciurus-hudsonicus/image-G99592.html
http://www.nhptv.org/natureworks/redsquirrel.htm
http://animaldiversity.ummz.umich.edu/accounts/Tamiasciurus_hudsonicus/

Mammals, Wildlife

Raccoon Information and Description

December 28, 2013 traderscreek

General: The common raccoon (Procyon lotor,) also referred to as the North American raccoon, is an opportunistic forager that is a common sighting in a vast array of habitats. This shy, nocturnal mammal is highly adaptable and has taken to living in close proximity to human populations. Native populations stretch across North America into northern South America and experience stable numbers and high success rates, earning them the distinction of ‘least concern’ on the IUCN Red List. Despite this success, raccoons are often thought of as pests because of their tendency to forage in trashcans and damage property.

Description: Raccoons can be easily recognized by their unique coloration and stocky, “well-rounded” build. Full grown, adults weigh an average of 14lbs. (and up to 24lbs.) and are 24” to 38” in length, with males reaching a mature size that is 10-30% greater than females. Raccoons, especially in northern environments or in preparation for winter, may develop a body mass that is up to 50% fat. Coloration may vary geographically, but their bodies are often grey, brown, buff, or reddish-brown, accented with black. Their fur is thick and long and is often a mottled combination of colors with a light base. Raccoons are best known for their signature black “masks” on their faces, accented by white fur around the nose, and bushy tails marked with 4 to 10 black rings. Their tails make-up about 45% of their overall body length and are used to store fat and balance. Juveniles have similar coloration to adults but are darker overall.

Raccoons have extremely dexterous paws that are similar in appearance to a human hand, creating tracks that resemble handprints. Their black paws have five toes that are sensitive, flexible and nimble, allowing raccoons to grasp, hold, climb and manipulate objects. Agile climbers, raccoons are capable of moving forward, backward, up and down trees (able to descend trees headfirst, unlike most climbers) and are able to survive a 35’ to 40’ fall. They generally walk or shuffle and are able to run as fast as 15 mph, although they only travel out of necessity for food or safety. Raccoons are also adept at swimming but because of their lack of waterproof fur, they only enter the water when necessary1.

In addition to a highly developed tactile sense, raccoons also have an acute sense of hearing and highly developed night vision. They are capable of making a variety of sounds, including purrs, snarls, whinnies, screams, growls, hisses, and whimpers. Raccoons can become quite aggressive when they or their young are threatened and are capable of killing a dog2.

While raccoons do not formally hibernate, they do become inactive for long periods of time, especially in northern climates. Raccoons sleep during these times and are able to maintain stable metabolic rates and body temperatures. Prior to this extended period, raccoons gorge themselves to increase their body fat and by the time they emerge can loose up to 50% of their total body weight3.

Raccoons may live up to 16 years in the wild, although most don’t make it past their second year of life. On average, raccoons live 5 years in the wild. There was one recorded instance of a raccoon reaching 21 years of age in captivity4.

Raccoons are susceptible to a number of diseases, some of which may affect people and pets. One common ailment is canine distemper, causing confusion, loss of coordination, and eventually death in raccoons. Canine distemper cannot be transmitted to immunized pets or people. The disease most associated with raccoons is the rabies virus. Symptoms can be similar to distemper, but may include aggressiveness, excessive salivating, and paralyzed hind legs. This disease can be transmitted to other animals and people. Raccoons commonly become infected with roundworms, although they typically do not experience any side effects. Unfortunately, infected raccoons excrete roundworm eggs, which can cause nerve damage if they are ingested by another animal and hatch. There are two known cases of human fatalities in New York State, which resulted from accidental infection of roundworms by a captive animal5.

Habitat: Raccoons are a highly adaptable animal and can be found in a variety of habitats, such as woodlands, farmlands, cities and suburbs, marshes, flood plains, and prairies. Despite this broad range, raccoons almost always locate their habitat near a source of water and prefer to reside in moist environments. Because of their adaptability and varied food preferences, raccoons are able to live within close proximity to humans.
They often build their dens in trees, but may also locate them in caves, buildings, homes or garages, rain sewers, or abandoned animal burrows.
Geographic ranges are generally .5 to 2 miles in diameter but may be as large as 6 miles in diameter and are typically not exclusive. Populations tend to be denser in cities rather than the wild.
Raccoons are at risk of predation by foxes, coyotes, wolves, bobcats, eagles, snakes (which prey on the young,) and owls but are most often killed by vehicles.

There are six species of raccoons, beside for Procyon lotor, that live almost primarily in tropical island habitats.

Location: Populations of the common northern raccoon may be found across the United States (except for some areas in the American southwest and the Rockies,) southern Canada, and northern South America. Populations have been introduced to parts of Asia and Europe and have experienced high survival and success rates.

Diet: Raccoons are omnivores that use their front paws and nimble fingers to forage for a variety of foods at night on land and in the water. Their diets include crayfish, frogs, turtles and turtle eggs, salamanders, fish, clams, worms, mice, insects (such as grasshoppers, crickets, and wasps,) voles, nestlings and bird eggs, and squirrels. Their diets also include vegetation, nuts, berries, fruits, and farm crops. These opportunistic feeders are best known for their tendency to steal garbage, food scraps and pet food, and have been known to dine on road kill; however, despite commonly being sighted at garbage cans, invertebrates make up the majority of raccoons’ diets.
Raccoons are commonly associated with “washing” their food (their name derived from the latin for “the washing bear.” 6) Despite popular belief, raccoons do not wash their food and don’t require the extra moisture for digestion. Scientists now believe raccoons use moisture to activate sensitive nerves on the hairless areas of their front paws in order to improve their tactile sense and more accurately identify the item they are about to consume.

Reproduction: Raccoons typically breed once a year, with mating taking place between February and June (the highest frequency of mating occurring in March.) Populations living in southern habitats tend to breed later than those in northern habitats. During the mating season male raccoons often expand their ranges to increase their exposure to females and females begin looking for dens. Female raccoons have been known to temporarily reside with their mates in the males’ dens until breeding has occurred. Males may remain with females for a brief period of time (up to a month before breeding up until the birth of the young) but do not remain to assist in post-natal care.

Raccoons are opportunistic when selecting sites for their dens, using tree or rock cavities, logs, attics, caves, or abandoned burrows.

The gestational period lasts for approximately 65 days and litters containing an average of 4 young are born between April and May (although litters may contain 1 to 7 young.) The young, also referred to as kits, are born blind and helpless, weighing under 3oz., and are cared for exclusively by their mothers. The kits open their eyes after 3 weeks and are able to stand between 4 to 6 weeks old. They use a variety of sounds to communicate with their mother, including mews, cries, and twitters. The young are weaned after 8 to 9 weeks at which point they begin following their mother out of the den to learn to hunt and climb. During this time their mother is extremely protective of her young and will aggressively defend them from predators. Outside of this maternal relationship, raccoons are generally solitary animals. A mother may be spotted protectively carrying her young by the scruff of their neck. By 5 months old, the kits regularly hunt alongside their mothers at night. They remain with their mothers through their first winter and then establish their own dens, often in close proximity to their birth den, when they are approximately10 months old.

Female raccoons reach sexual maturity before 12 months of age, while males require 24 months to become fully mature7.

Notes of Interest: The majority of raccoon populations have continued to grow and have experienced extreme success and stability due to their highly adaptable nature. However, some isolated populations living in tropical island habitats are experiencing declining numbers8.

Historically, raccoon pelts were valued in the fur industry. “Coon” coats were fashionable in the 1920’s, when a single pelt went for $14 (equivalent to $185.00 today.) Today, raccoon pelts are less desirable but are sometimes sold as imitation mink, seal or otter9.

Keeping a raccoon as a domestic pet is an illegal practice in most states and requires the proper license in other states. Yet, some people still choose to do so. Before making the decision to keep a raccoon as a pet, consider how their characteristics would fit into your life: they are nocturnal and are often not awake during the day, they are shy and tend to keep their distance from humans, they can become extremely aggressive when cornered and they may carry rabies, among other diseases. Raccoons can also cause major destruction to property.

How can you prevent raccoons from frequenting your property?
Store any pet food that’s outside in containers with tight-fitting lids. Avoid feeding pets outside. If pets must be fed outside, don’t leave excess food in the dishes and keep dishes in well-lit, enclosed areas, if possible.

Keep garbage in metal cans with tight-fitting lids and, if possible, in well-lit areas near activity. If problems persist, strap the lid down or suspend the cans off the ground.

Enclose gardens, if necessary, with an electric fence.

Fill any openings in your home where raccoons can enter. Keep in mind that raccoons can get through very small spaces. However, before you permanently fill the hole, place a temporary cover or test such as twigs, leaves or flour in the hole and watch for disturbances. This will verify whether raccoons are entering and exiting through that location. Also be sure there has been no den built in your home or structure. If there is evidence of a den, contact an animal control specialist10.

Footnotes

1. http://animaldiversity.ummz.umich.edu/accounts/Procyon_lotor/
2. http://www.fcps.edu/islandcreekes/ecology/raccoon.htm
3. http://animaldiversity.ummz.umich.edu/accounts/Procyon_lotor/
4. http://animaldiversity.ummz.umich.edu/accounts/Procyon_lotor/
5. http://www.dec.ny.gov/animals/9358.html
6. http://animaldiversity.ummz.umich.edu/accounts/Procyon_lotor/
7. http://animaldiversity.ummz.umich.edu/accounts/Procyon_lotor/
8. http://animaldiversity.ummz.umich.edu/accounts/Procyon_lotor/
9. http://animaldiversity.ummz.umich.edu/accounts/Procyon_lotor/
10. http://www.dec.ny.gov/animals/9358.html

http://animals.nationalgeographic.com/animals/mammals/raccoon/
http://www.fcps.edu/islandcreekes/ecology/raccoon.htm
http://www.nhptv.org/natureworks/raccoon.htm
http://www.dec.ny.gov/animals/9358.html
http://animaldiversity.ummz.umich.edu/accounts/Procyon_lotor/
http://science.howstuffworks.com/zoology/mammals/raccoons-wash-food1.htm

Mammals, Wildlife

Red Fox – Vulpes vulpes

December 10, 2013 traderscreek

General: The Red Fox (Vulpes vulpes) is a clever and cunning mammal, known for its adaptability and broad geographic range, which has expanded relative to human populations. A member of the canidae family, the Red Fox is closely related to the domestic dog, coyotes and wolves and is the largest of all species of foxes. With growing and stable populations, the Red Fox is unique from other fox species in that it is not listed as endangered in any geographic area.

Description: The largest of the Vulpes species, the Red Fox reaches a mature length of 18” to 34”, standing approximately 16” tall. Their full-grown weight ranges from 6.5lbs. to 24lbs., males typically larger than females by as much as 25%. Mature size is partially dependent on geographic location. Populations living in southern desert climates and southern parts of North America tend to be smaller, on average, than populations in northern European habitats. Generally, northern populations tend to have a greater body mass than southern populations.

Anatomically, the Red Fox bear a similar appearance to dogs, coyotes, and wolves, all classified in the canidae family. They have conical muzzles, prominent pointed ears, and tail glands located on the upper portion of the root of the tail, within the dermis. The dental composition is also similar to other members of the canidae family, with molars built for crushing, and pointed premolars. The tooth row stretches half the length of the entire skull. The front paws have five claws and the rear have four. The first digit of each paw, called the dewclaw, is clawed but otherwise simple in structure and does not come in contact with the ground1.

Red Foxes are easily identifiable by their thick coats that range in color from rusty-red, red-brown, or yellow-red, coving their backs, shoulders, and head. Two color variations of the Red Fox exist, including the Silver Fox, making-up 10% of Red Fox populations and silver to nearly black in color, and the Cross Fox variation, a hybrid of the Red Fox and Silver Fox that accounts for 25% of all Red Foxes, with reddish-brown fur and black stripes across the back and shoulders. Red Foxes have white or gray undersides, chins and throats. The rear may be covered in red fur or gray fur, similar to the underside. The bottoms of the legs and pointed, erect ears are black and the nose is either black or dark brown. The eyes of mature Red Fox are yellow. About half the length of a full-grown Red Fox is the bushy, cylindrical tail. The tail, 12” to 22” in length, is typically a combination of red and black and has a white or black tip. The tail of the Red Fox not only aids in balance, but also provides warmth and protection from extreme weather conditions and is used to signal and communicate with other foxes.

Red Foxes are shy animals that are rarely seen during the day. This nocturnal species is most active during twilight hours and at night. Unlike wolves, which are social animals that form packs, Red Foxes are solitary and generally live alone outside of the mating season. They are active year round and only inhabit a den during periods of reproduction. Home ranges are established and used throughout the life of a fox. These ranges are usually distinct from other ranges since Red Foxes are known to be territorial. These ranges may be 2 sq. miles to 4.5 sq. miles in ideal habitats and often contain one adult male and one or more adult females with their young. In habitats with poor or limited food supplies and during winter months, home ranges may expand to include 7.5 sq. miles to 20 sq. miles. In poor conditions, Red Foxes are capable of traveling several miles in a single day. They are a highly mobile species and are able to reach 30mph, jump obstacles over 6’ tall, and span 15’ in a single bound2. In the wild, Red Foxes live an average of 2 to 4 years, but have been known to live to 12 years old in captivity.

Red Foxes use a variety of methods of communication, including facial expressions, tail gestures, scent marking and vocalizations. Red Foxes use urine, feces, and glandular secretions as scent posts. Red Foxes are known to have unique voices and are capable of making upwards of 28 noises, used to communicate in close range and over distances. These noises include a dog-like bark and a scream, emitted when a fox becomes alarmed. In addition to their vocal abilities, Red Foxes have advanced senses of touch, smell and sight3.

Habitat: The Red Fox is a highly adaptable species whose populations are stable and wide spread in a variety of habitats, due in part to their ability to thrive in human-modified environments. They are found at elevations ranging from sea level to 14,500’, in forests, tundra, prairies, mountainous regions, deserts, grasslands, urban and suburban areas, and farmlands. Red Foxes prefer habitats that offer a mixture of vegetation and cover, living in brush piles, root systems, hollowed logs, or ground dens.

Red Foxes establish individual or family dens within their home ranges, used for protection during winter months and for birthing and raising young. These dens may be used for several generations. Their main dens are often supplemented with emergency burrows, multiple entrances, and pathways that connect the dens to food stores or hunting areas4. Red Foxes commonly steal dens from other animals, such as rabbits or woodchucks.

Within their habitats, Red Foxes have few predators. The young are at the highest risk of predation, but pups and adults are preyed on by hawks, owls, coyotes, and wolves.

Location: The Red Fox has the largest geographic distribution of all members of the canidae family. Their range has expanded alongside human populations, especially in areas where wolf populations are tightly controlled, eliminating a major predator and competitor of the Red Fox. Native populations are found across the northern hemisphere, throughout North America, northern parts of South America, Asia, Europe, and northern Africa. Populations were introduced to Australia and the Falkland Islands5 in the mid 1800’s as a sport animal.

Diet: Red Foxes are omnivores whose diets consist mainly of small mammals, such as mice, birds, squirrels, rabbits, opossums, woodchucks, skunks, shrews, voles, and moles. However, as opportunistic feeders, they will also consume fruits, vegetables, nuts, fish, worms, frogs, lizards, turtles, crustaceans, insects, domestic dogs and cats, and even carrion (decaying flesh) and garbage. With their excellent sense of hearing, Red Foxes are capable of picking-up the noises of underground animals, which are dug up and eaten. Red Foxes most often stalk their prey, quietly approaching before running the prey down and pouncing. Red Foxes are solitary hunters and do the majority of their hunting during twilight or at night, typically consuming .5 to 1kg of food each day6. Red Foxes are unique in that they are one of the few predators that store caches of food for future consumption.

Reproduction: Red Foxes are typically monogamous breeders, but it is not uncommon for males to have multiple mates, who may live together in the male’s den. A red fox group will not, however, have more than one mating male since males become territorial and aggressive during the breeding season. It is also possible for a mating pair to share their den with non-breeding females who contribute to rearing the young. Red Foxes reach sexual maturity by 10 months of age and breed annually. Estrus and breeding is partially dependent on geographic location, generally occurring in December or January in southern habitats, from January to February in central locations, and in February to April in northern areas. Females’ estrus period lasts from 1 to 6 days and ovulation does not require copulation but is spontaneous7.

Before females (or vixens) give birth, Red Foxes create a maternity den, which may be used for several years. These dens are created by enlarging another animal’s abandoned burrow, or within a hollow log, root cluster, cave, or brush pile. These dens usually have wide entrances (about 3’ wide) and multiple escape holes, and are lined with dry vegetation. Females stay in or around the maternity den prior to birth, receiving sustenance from mates. Gestation lasts from 50 to 60 days and females give birth to an average of 5 pups, although litters may contain from 1 to 12 pups. Pups are born weighing between 50g to 150g, and are blind and grey or brown in color. Their eyes open within 9 to 14 days and the signature red coat grows-in by around one month of age. Both parents, and sometimes offspring from previous litters, provide care to the young until the young are old enough to provide for themselves. Pups are fully weaned by 8 to 10 weeks old and are fed regurgitated meat by their mothers. Mothers begin bringing live prey to the pups in the den so they may learn to hunt and at 4 to 5 weeks old pups begin following their parents out of the den to learn to hunt. Pups live with their parents through their first fall (female pups may stay with their parents longer,) at which point they disperse to establish territories of their own. These new home ranges may be as close as 6 miles and as far as 250 miles from their birth dens8. Once the pups have left, parents may separate.

Notes of Interest: Red Foxes are one of the most common carriers of the Rabies virus. Red Foxes are a nocturnal species, and caution should be used around a Red Fox that is active during the day, as this might indicate an infected animal.

Red Foxes are a staple of the fur industry and are more commonly raised on fur-farms than any other fur bearer9.

http://animals.nationalgeographic.com/animals/mammals/red-fox/
http://www.fcps.edu/islandcreekes/ecology/red_fox.htm
http://animaldiversity.ummz.umich.edu/accounts/Vulpes_vulpes/
http://www.dec.ny.gov/animals/9354.html
http://www.dnr.state.mn.us/mammals/redfox.html
http://www.mnh.si.edu/mna/image_info.cfm?species_id=420

Mammals, Wildlife

Opossum – Didelphia virginiana

December 7, 2013 traderscreek

General: The opossum (Didelphia virginiana) is one of the oldest known mammals, having been traced back 70 million years through fossilized remains. Over 60 species of this common mammal are now found across North and Central America. The opossum is the only marsupial found in North America1 and is notable for the unique presence of a pouch that is used to protect, nourish and raise young. You may come across one of these nocturnal animals wondering quietly at night or even hanging from their prehensile tails from a tree branch. Unfortunately, many opossums are killed by automobiles because of their tendency to eat carrion. Despite their high mortality rates, opossums are widespread with healthy populations and are listed as least concern on the IUCN Red List.

Description: Opossums are slow, clumsy heavyset mammals that reach a mature weight of 8.8 to 13.2lbs. and nose-to-tail length of up to 30”, with males being slightly larger than females. They have easily identifiable elongated heads with conical snouts and long whiskers. The skull of the opossum contains 50 teeth, more than most other mammals within their habitats (a feature that is indicative of the opossum’s ancient lineage2.) Opossums are possibly best known for their long, tapered prehensile tails that are scaly in appearance. This type of tail is used as a fifth limb and is adapted for gripping and wrapping, aiding in climbing and allowing opossums to hang from their tails for short periods of time. Opossums also have hand-shaped feet with sharp claws that aid in climbing and an opposable hallux located on the interior of each rear foot. A hallux functions similar to a thumb and aids in gripping3. Opossums use these digits to groom their fur, faces, and front feet4. As members of the Didelphidae family (and the only marsupials found in North America,) female opossums have wooly, fur-lined pouches on their abdomens that are used to carry their young.

The coloration of opossums varies by region, but opossums generally appear gray with small black eyes set into a lighter or white face, black feet with white or pink toes, and leathery black ears with white or pink tips. Their coloration is a result of a dense white undercoat that is tipped in gray (or sometimes brown) with dark or black guard hairs. Southern populations tend to have a sparser undercoat. Albino mutations are not uncommon and result in a white coat, ears and feet and pink eyes5.

Opossums are nocturnal and use their senses of smell to locate food. While their level of intelligence is undetermined, opossums are known to have poor and limited social interactions. Males tend to be solitary and aggressive when in close proximity to other males. Females often live in groups. Opossums exhibit a number of behaviors when threatened (both aggressive and passive,) including growling, urinating, defecating and belching. Outside of growling and audible aggressive displays, opossums are relatively quiet. Most notably, opossums may play dead or “play ‘possum” when threatened. This includes rolling over and lying stiff with closed or fixed eyes, drooling, sticking out their tongues, and slowing their breathing until almost undetectable. This behavior may last for hours until the threat has passed. Opossums may run from threats and have also been known to swim to escape danger.

Opossums do not hibernate but will retreat into dens during extreme temperatures to avoid the risk of frostbite on their hairless extremeties6.

Habitat: Opossums are skilled climbers and nest and spend much of their time in trees in habitats including deciduous forests, farmlands, and open forests. They may be found in arid environments, but prefer moist habitats, including marshes, streams, and swamps.

Opossums do not establish territories (except for when females tend to remain in a small range when raising young7.) Instead, opossums tend to constantly move in unusual patterns in search of food.

Within their habitats, opossums fall prey to many predators, such as birds of prey, foxes, coyotes, and humans, who often hit opossums with cars. The young are susceptible to predators such as snakes and birds of prey8.

Location: Opossums may be found across North and Central America, including parts of the United States east of the Rockies as well as along the west coast. Opossums were introduced to California in 1890 and proceeded to spread along the west coast9. Their range continues to spread northward and populations can now be found in southwestern Ontario and British Columbia, Canada.

Diet: Opossums are omnivorous scavengers whose diets range from human garbage and carrion, to grass, fruit, nuts, berries, insects, snails, mice, birds, worms, and pet food. Their developed senses of smell allow them to locate sources of food at night, when they are most active.

Reproduction: Female opossums may have up to 3 litters in a year, depending on geographic location, at anytime from early spring through summer. Females nest in trees or dens built by other animals. The young are born approximately two weeks after mating occurs and the last litter of the year may still be traveling with the mother when the first litter of the next year is born10. Males offer no parental care or support beyond fertilization. Females may give birth to up to twenty young, born helpless and the size of jellybeans, but litters typically contain 5 to 8 babies. Immediately after birth, the young crawl into the mother’s pouch in search of one of her thirteen teats. Some young do not survive the trip to the pouch and only those that make it to the pouch and find a teat have a chance at long-term survival. The young develop within the pouch attached to the teats for approximately a month, at which point they begin leaving the pouch for periods of time to travel along with their mother, sometimes atop her back or clinging to her tail. The young may remain with their mother for as long as three months11.

Few opossums live past 18 months old because of high mortality rates (many deaths due to car accidents.) The oldest opossum captured was determined to be 3 years old12.

Notes of Interest: Opossums are one of the oldest mammals on Earth. Fossilized remains have determined that opossums existed during the age of the dinosaurs, approximately 70 million years ago13.

Opossums are hunted as furbearers as well as food.

Opossums earned their westernized name in 1608 when first spotted by Captain John Smith, derived from the Algonquin word for ‘white animal,’ apasum14.

Footnotes
1. http://animals.nationalgeographic.com/animals/mammals/opossum/
2. http://www.in.gov/dnr/fishwild/3367.htm
3. http://www.nhptv.org/natureworks/opossum.htm
4. http://animaldiversity.ummz.umich.edu/accounts/Didelphis_virginiana/
5. http://www.in.gov/dnr/fishwild/3367.htm
6. http://www.nhptv.org/natureworks/opossum.htm
7. http://www.opossum.org/
8. http://animaldiversity.ummz.umich.edu/accounts/Didelphis_virginiana/
9. http://animaldiversity.ummz.umich.edu/accounts/Didelphis_virginiana/
10. http://www.in.gov/dnr/fishwild/3367.htm
11. http://www.in.gov/dnr/fishwild/3367.htm
12. http://animaldiversity.ummz.umich.edu/accounts/Didelphis_virginiana/
13. http://www.opossum.org/
14. http://www.nhptv.org/natureworks/opossum.htm

http://animals.nationalgeographic.com/animals/mammals/opossum/
http://www.opossum.org/
http://www.nhptv.org/natureworks/opossum.htm
http://www.in.gov/dnr/fishwild/3367.htm
http://animaldiversity.ummz.umich.edu/accounts/Didelphis_virginiana/

Mammals, Wildlife

Javelina – Pecari tajacu

December 6, 2013 traderscreek

General: Collared Peccaries (Pecari tajacu,) also known as Javelinas because of their javelin-like tusks, are members of the peccary family, and

bear a physical resemblance to (and are commonly mistaken as) wild pigs. These highly adaptable mammals have spread their range northward and now inhabit territories from northern Argentina to the American Southwest. Collared Peccaries are one of the most popular game animals in the southern United States and their populations remain stable and healthy. Listed as Least Concern on the IUCN Red List, these animals are prized by some for their hides, kept by others as domesticated farm pets, and considered nuisances by others who have to tolerate them on their property in search of an easy meal.

Description: Collared Peccaries are sometimes mistaken for wild pigs because of their physical appearances. Their coarse, bristly hair and hog-like snouts lend to this misnomer.

Adult peccaries measure 12”-19” at the shoulder, are 30” to 39” long and weigh an average of 33lbs. to 55lbs1. They have large heads with short, nearly straight tusks (that earned the collared peccary its common name, javelina- after the tip-shaped spear,) crushing molars, small legs and hoofed feet (with four toes on the front feet and three toes on the rear, due to the absence of dewclaws.) The Collared Peccary earned its nickname “musk hog” because of its posterior, dorsal musk gland, used to mark territory and to identify individuals. Females have two sets of inguinal mammary glands2.

Collared Peccaries have grizzled gray-black coats, with yellowish cheeks, dark dorsal manes and white or yellow coloration extending from the mane, across the shoulders and onto the throat.

Sexual dimorphism is not strongly articulated within this species. However, the young are born with a reddish or yellow overall coloration.

Collared Peccaries activity levels adjust according to the climate and time of year. During the summer they are most active at night, sleeping in the shade during the heat of the day. In the winter, peccaries commonly forage during the day in order to take advantage of the sun and at night sleep in groups to share body heat3.

Collared Peccaries are a highly social mammal, living in stable groups with complex communication, social hierarchies, and relationships. These groups, numbering from five to up to thirty individuals, maintain a gender ratio of roughly 1:1 and are comprised of codependent individuals, relying on the each other to eat, sleep, groom, and survive. Each group contains a dominant male who is responsible for the majority of breeding. Typically, the rest of the social hierarchy is determined by size. Within these groups, it is not uncommon for a feeding group to break away from the herd and become the start of a new group4.

Collared Peccary groups have territories that are determined by the number of individuals within the group and food resources and can be 6 to

1260 hectares in size5. These ranges rarely overlap with other peccary groups. These territories are fiercely defended by males and females within the group, who establish and mark their borders with glandular secretions and feces. Collared Peccaries may also aggressively defend their territories, by squaring off, chattering their teeth, charging, biting, or locking jaws. When greeting and identifying other group members, individuals use their dorsal glands for scent recognition and rub together along the lengths of their bodies.

Collared Peccaries have poor eyesight. They do, however, have good hearing. Because of this, vocalizations play an important role in their social interactions. Collared Peccaries are able to make upwards of fifteen vocalizations, used to communicate alarm, submission and aggression6.

Habitat: Collared Peccaries live in a range of habitats from tropical rainforests and forests in South and Central America, to arid, desert or dune habitats of the American Southwest (including Saguaro deserts and mesquite habitats.) Collared Peccaries have also adapted to living in urban and residential environments, attracted to the ample food sources.

Within their habitats, coyotes, bobcats, pumas, jaguars, and humans prey upon Collared Peccaries7.

Location: Collared Peccaries are the only species of Peccaries (there are three total) to live outside of South America8, with populations of fourteen subspecies spanning from northern Argentina, across Central America, and into the American Southwest (Texas, New Mexico, and Arizona9.)

Diet: Collared Peccaries diets are dependent on seasonal changes, including temperatures and the availability of food sources. Temperatures determine foraging practices, with peccaries tending to feed during the day in the winter to take advantage of the heat from the sun and later at night in the summer to avoid extreme heat.
Collared Peccaries are mainly herbivorous, and their diets are primarily composed of agaves and prickly pears (food sources that are well suited for the peccaries dry habitats because of their high water contents, which eliminates the peccaries need to frequent water holes.) Additionally, peccaries eat roots, bulbs, beans, berries, nuts, fungi, and grasses, as well as fish, eggs, some reptiles and amphibians, insects, and carrion. A highly adaptable species, Collared Peccaries have also learned to frequent urban environments, where they become nuisances in search of food. The stomach of the collared peccary is complex and is able to break down coarsely chewed food10.

Reproduction: Collared Peccaries are the only hoofed animals found in the western hemisphere that have breeding seasons not constrained by season, but rather climate. Collared Peccaries can breed year round if conditions allow and tend to have more young during rainy years. Almost all breeding is completed by the dominant male of the herd (subordinate males may not approach a female in estrus11.)

Pregnant females leave the group before having their young to avoid the newborns being eaten by other group members. After a gestation period of 140 to 150 days, females give birth to one to three reddish or yellow young, weighing 1.5lbs, within an earthen den or hollowed log. At a day old, the young are able to travel with their mother and the family may safely return to the herd. Females from previous litters may help the mother care for her young, which are weaned by two to three months of age.

Females reach sexual maturity between eight and fourteen months old, whereas males are fully mature by eleven months old.

Collared Peccaries have been known to live up to 24 years old in captivity12. Some populations, however, are being threatened due to deforestation and destruction of habitat.

Notes of Interest: The Collared Peccary earned its common name, Javelina, because of the resemblance their tusks bear to the tip of a javelin13.

Peccaries were commercially hunted for their hides until 1939, when the species received the status of game animal14. Now, this big game species is prized as one of the most important game species in states such as Arizona ad Texas. In Texas alone over 20,000 peccaries are shot during each hunting season. Each year, approximately 10,000 peccary hides are still exported from Peru15.

It is not uncommon for young peccaries to be captured and kept as domestic farm pets16.

http://animaldiversity.ummz.umich.edu/accounts/Pecari_tajacu/
http://www.mnh.si.edu/mna/image_info.cfm?species_id=246
http://www.nhptv.org/natureworks/peccary.htm
http://www.nsrl.ttu.edu/tmot1/tayataja.htm

Mammals, Wildlife

Deer Mouse – Peromyscus maniculatus

December 5, 2013 traderscreek

General: The deer mouse (Peromyscus maniculatus) is a highly adaptable North American species that is more widespread than any other species of mouse in this geographic range. They are often considered pests, inhabiting human dwellings, invading food and grain stores and carrying potentially fatal viruses.

Description: The deer mouse is a small, slender species, reaching a mature weight of 10g to 24g  and a full-grown length of 4.5” to 8.75” (the tail comprising one-third to around one-half the total length of the body.) Physical characteristics vary geographically. For example, populations living in woodlands tend to be larger overall than prairie populations. In general, deer mice have pointed noses, long vibrissae (like whiskers,) prominent, black eyes, and large ears covered in fine fur. Deer mice have forelimbs that are shorter than their hind limbs and hind feet that are approximately .8” in length.

Deer mice have short, fine, dense fur that is gray to red-brown across their bodies, and white or off-white on their undersides. They often have white hair resembling tufts at the bases of their ears. One of the most distinguishing characteristics of the deer mouse is the two-toned tail, which is covered in fine hair, dark on top and lacking any pigment on the bottom. Compared to the tails of other species of North American Mice, the coloration on that of the deer mouse is much more sharply defined. In general, deer mice are furrier than both the White-Footed Mouse and the House Mouse1.

The deer mouse is a nocturnal species that tends to be most active at twilight. It is a predominantly terrestrial species, that uses walking, running and sometimes leaping as its main modes of transportation, although the deer mouse is also a skilled climber2. Tracks are usually in groups of four with a trail width less than two inches.

Although the deer mouse is generally a solitary animal, basic social units do emerge during breeding seasons or cold months, when ten or more mice may huddle to conserve body heat (during extreme cold, mice may reduce their body temperatures and enter a daily torpor to conserve their energy.) These basic units often consist of mature males and females and some young of varying ages. Deer mice maintain home ranges that vary in size from 2600 square feet to over 32,000 square feet (that of males generally being larger than that of females.) Reproductive females are most territorial of their ranges and rarely overlap ranges with other females, since intruding females are known to commit infanticide. Ranges of males and females may overlap. The majority of activity occurs in close proximity to a mouse’s nest and food caches, constructed below ground, in a tree cavity, in a brush pile, stump or log, or within a human dwelling3. The nests are cup-shaped or spherical and made of vegetable matter, fur, or feathers. During the winter, activity becomes especially restricted and occurs mainly below the snow around the nest or within the nest for up to days at a time4.

Deer mice have highly developed senses of hearing, sight, smell and touch. They communicate with a variety of physical (postures, drumming,) chemical (scent marking,) tactile (grooming,) and vocal cues (with sounds including squeaks, trills, shrieks, and buzzing as well as drumming created by using the front paws possibly as a warning5.)

Deer mice can live up to eight years in captivity, but in the wild, do not often live longer than one year6.

Habitat: A highly adaptable species, the deer mouse can be found in every terrestrial habitat across all elevations, although their preference is for cool, moist, forests habitats. Inhabited zones include boreal and alpine forests, deserts, brush lands, prairies, agricultural areas, grasslands, and arid tropical areas.

Deer mice are a dietary staple of many carnivorous mammal and avian species, including snakes, owls, foxes, bobcats, and coyotes, to name a few7.

Location: Deer mice populations stretch across North America, from Alaska and Canada to Mexico. They are absent only in the southeastern United States and certain coastal sections of Mexico. This species is more widespread than any other species of mouse in North America, both geographically and ecologically8.

Diet: Deer mice are omnivorous and consume a diverse diet of insects, snails, earthworms, seeds, fruit, fungi, nuts, and plant matter. They are also known to eat carrion and at times, their own feces. Their sharp incisors are capable of breaking hard seeds and exoskeletons.

Deer mice cache food, especially in cooler climates or during cold months. Caches hold up to two cups of food each, consisting mostly of seeds, and are located in the ground or within cavities in trees. Despite this hoarding, starvation is a major cause of death for deer mice during winter months9.

Reproduction: Deer mice are polygamous and may breed throughout the year, although the majority of breeding takes place during warm months when there is ample food. During favorable breeding months, deer mice breed, on average, every three to four weeks, based on female estrous cycles of approximately five days.

Breeding pairs may inhabit the same nest, but females often drive males away in order to raise the young along. Typically, males offer no post-natal care. Females have a gestation period of 22 to 25.5 days. Females can experience a post-partum estrus and become pregnant shortly after one gestation period ends. The gestation period for a lactating female tends to be longer, lasting from 24 to 30.5 days. Litter size may range from one to eleven young, but contain, on average, five young. Females’ first five to six litters tend to increase in size consecutively, at which point they begin to decrease in size. The young are born hairless and blind, weighing 1.5g. Juvenile development is rapid. Hair begins to grow by the second day, the ear canals open by the tenth day, and the eyes open by the fifteenth day of life. The young cling to the mother’s nipples as she travels or are held in her mouth (one at a time.) The young are weaned in 25 to 35 days, at which point they may leave the nest and live independently. If the mother becomes pregnant with a second litter, she will eject the first litter from the nest10 (or in some instances, will leave the nest to be used by her mate with the older litter and find a new nest for the second litter11.)
Deer mice reach sexual maturity within 35 to 50 days, and females’ first estrus occurs by 49 days old12.

Notes of Interest: Deer mice are known carriers of a strain of Hantavirus, Sin Nombre virus. Humans who contract this virus develop Hantavirus pulmonary syndrome, a disease that is usually fatal13.

Deer mice that were marked and released by biologists were observed traveling 2 miles over the course of two days to return to their nest14.

http://animaldiversity.ummz.umich.edu/accounts/Peromyscus_maniculatus/
http://www.esf.edu/aec/adks/mammals/deer_mouse.htm
http://calmzoo.org/animals/deer-mouse/

TradersCreek.com

Category Archives: Mammals

Red Squirrel – Tamiasciurus hudsonicus Information

Raccoon Information and Description

Red Fox – Vulpes vulpes

Opossum – Didelphia virginiana

Javelina – Pecari tajacu

Deer Mouse – Peromyscus maniculatus

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