Red Squirrel

The American red squirrel is one of the most common mammals in all of North America.

As a type of rodent, these agile tree climbers are found almost anywhere with mixed hardwood and evergreen conifer forests. They’ve also adapted very well to urban and suburban environments. Renowned for their excellent memory, American red squirrels will bury their food for the winter and then return to it later to feed. While easily dismissed for their small size and ordinary appearance, they are actually quite remarkable creatures.

5 Incredible Red Squirrel Facts!

• Red squirrels play an important environmental role by dispersing seeds and fungi throughout the ecosystem. After burying a cache of food, the squirrel sometimes forgets about it or fails to return, leaving the seed germinating.
• One of the more amazing facts is that squirrels can remember the location of thousands of nuts they buried during their preparation for the lean winter months. Their brain even seems to expand in size and develop more neural activity during the fall.
• The squirrel’s big, bushy tail is not just for show. It helps to provide balance and regulate body temperature.
• Another amazing fact is that squirrels have a remarkable ability to jump vertically some 4 to 5 feet and horizontally around 10 feet. Like cats, they seem to land on their feet without any problem by twisting their bodies in the air and rotating their tail.
• There are 25 recognized subspecies of American red squirrels, isolated by region.

Scientific Name

The scientific name of the American red squirrel is Tamiasciurus hudsonicus. It was named after Hudson Bay, where it was first cataloged in 1771. Its closest living relatives in the genus of Tamiasciurus are the Douglas squirrel and Mearns’s squirrel, both of which have a more grey-brown body color. The American red squirrel should not be confused with the Eurasian red squirrel, which is a separate species in a different genus.

Species

The American red squirrel is one of three tree squirrel species in the genus Tamiasciurus, also called the pine squirrel. The others are the Douglass squirrel, (T. douglasii), and the southwestern red squirrel, (T. fremonti). More names for the American red squirrel are the Hudson’s Bay squirrel and chickaree.

There are 23 subspecies of American red squirrels listed at the end of the article.

Evolution

The earliest fossil evidence of squirrels was found in western North America and dated to around 36 million years ago. Six million years later – fossil records indicate that squirrels appeared in Europe. During that time the Bering Strait land bridge provided passage for many different species – including squirrels – from North America. Squirrels show up in African fossil records shortly after they collided with Eurasia about 18 – 20 million years ago. After that, squirrels evolved and adapted to their diverse environments – into the over 200 species known today.

Appearance

The red squirrel can be identified by its small but stout body, relatively large paws, bushy and curling tail, and erect ears with small tufts of fur. Their long incisors, which help them cut through tough material, can grow 6 inches in a year and must be worn down by eating and gnawing. The back and face are covered with a rusty red color that turns slightly grey in the winter, while the underside of the body and the ring around the eyes are white. There are also black parts around the tail and nose.

Red squirrels are about the same size as a large book. They weigh between 7 and 10 ounces and measure about 10 to 15 inches with the tail included. Both males and females are similar in appearance.

Red Squirrel vs. Grey Squirrel

In North America, there are several species of grey squirrel, including the eastern grey squirrel, the western grey squirrel, the Arizona grey squirrel, and the Mexican grey squirrel, all of which belong to a separate genus, Sciurus. Besides the obvious differences in color, the red squirrel is about 30% to 50% smaller than other types of tree squirrels. It also has tufts of fur on the ears and lacks the multi-colored “halo” effect around the tail.

Behavior

The American red squirrel is a true expert at foraging for limited resources. The peak of their activity occurs in the fall when they prepare to stock up on food for the winter. The squirrel will bury thousands of different nuts every year in random underground caches around its territory. In order to find where they hid the food, the squirrel must rely on its excellent memory. Some studies performed on a similar grey squirrel demonstrate that they can still recall the solution of a puzzle two years after first learning about it.

For a small number of squirrels, the arduous process of nut collection may be too much work. They will spy on other squirrels that bury their food and then resort to outright theft. This competition for food may be a matter of life and death since the winter can be harsh and unforgiving. As the temperature drops, the squirrel becomes progressively more lethargic and inactive. It does not quite enter a state of hibernation, however, since it will leave the nest to forage and eat at least once a day.

Red squirrels are highly territorial in nature and do not tolerate the presence of intruders. Each one maintains a territory a few acres in size. Their aggression tends to ramp up in the fall as they prepare for the mating season and the lean winter months. Squirrels will construct their nests somewhere within their territory and close to the food caches.

They prefer to inhabit the natural hollows and cavities of trees, but if these are not available, then they will usually build a nest in branches, underground burrows, and even human homes and buildings. They are very discriminating in their choice of homes. Tree diameter, the structure of the branch, and the existence of escape routes are all factored in. The nests will be lined with grasses, moss, feathers, leaves, and fur.

In order to communicate, the red squirrel makes a cacophony of different chirping, growling, screeching, and buzzing sounds. Most of these sounds serve as a warning against predators, threats, or anything else that encroaches on its territory. The sounds also help aggressive males drive off reproductive competitors in the breeding season.

A scent marking will be the first sign that the squirrel is intruding on someone else’s territory. This will usually be enough to drive away intruders and prevent unnecessary conflicts. But if these incursions persist, then a fight may break out among the squirrels.

Habitat

The red squirrel can be found almost anywhere in Canada and the United States (including Alaska) with plenty of coniferous tree cover. This means it’s much less common in the Great Plains states, the southeastern US, and parts of the Pacific coast. It seems to prefer a habitat of mixed hardwood-conifer forests with spruce, pine, hemlock, or fir trees in elevations of up to 2,500 feet.

Predators and Threats

Many red squirrels will die to predation and natural attrition yearly, but this species does not face any significant threats in the wild. Habitat loss is generally not a problem on the whole. While squirrels may lose some territory to logging and development, the amount of tree cover has remained steady in the United States. Perhaps the biggest problem is that red squirrels are sometimes outcompeted for resources, especially by their larger and bulkier grey cousins.

What eats the red squirrel?

The red squirrel is preyed upon by weasels, martens, minks, foxes, lynxes, snakes, eagles, owls, and hawks. Humans have historically hunted them for food and for their fur.

Diet

What does the red squirrel eat?

The red squirrel primarily feeds on seeds and nuts. These highly opportunistic animals will supplement their diet with the occasional piece of fruit, mushrooms, tree sap, flowers, insects, or bird eggs. In order to draw out the tree sap, the squirrel will puncture the sap-carrying vessels and then harvest it later. But it will only resort to this if other food is not widely available. The green seeds of conifer trees appear to be the squirrel’s favorite type of food.

Reproduction and Life Cycle

The red squirrel has one or two defined breeding seasons per year, usually lasting between March and May and between August and September. Males compete against each other quite aggressively to acquire the most mates. Individual pair bonding is rare. The female may only be in estrus (meaning sexually available) for one day every breeding season. In this short window, the males will spend their energy pursuing the female and driving off other competitors.

After a pregnancy period lasting about a month, the female gives birth to an average of four (though as many as eight) young at a time. These baby pups are born completely helpless and without much fur. The mother assumes sole responsibility for raising the young, while the male usually returns to his own territory and has no other contact with the mate and the offspring.

Lactation occurs within the first 70 days of birth. After each baby is weaned off the milk, the pups are expected to become fully independent. Sometimes, when the mother is ailing, the newly mature squirrel may receive some pieces of her territory, like the heirs to an estate. This will significantly increase their odds of survival.

Red squirrels have a very high birth rate, probably because they also have a very high youth mortality rate as a baby due to predation, lack of food, and harsh environmental conditions. Only about a quarter of them will survive their first year of life. If they do grow out of the juvenile phase, however, they will have a lifespan of about five years. The oldest squirrel on record lived about 10 years in the wild.

Population

The American red squirrel is currently classified as a species of least concern by the IUCN Red List. While population numbers are not well-known, this species probably numbers in the millions. However, this obscures some variability in the population numbers of some local subspecies. The Mount Graham red squirrel of Arizona, for instance, is known to be endangered with only a few hundred individuals remaining in the wild.

List of the 23 Subspecies of American Red Squirrel