Abert's Squirrel

## Description

Abert's squirrel or the tassel-eared squirrel (Sciurus aberti ) is a tree squirrel in the genus Sciurus native to the southern Rocky Mountains from the United States to the northern Sierra Madre Occidental of Mexico, with concentrations found in Arizona, New Mexico, and southwestern Colorado. It is closely associated with, and largely confined to, mature ponderosa pine forests. It is named in honor of the American naturalist John James Abert; nine subspecies are recognised. It is recognizable by its tufted ears, gray color, pale underparts and rufous patch on the lower back. The squirrel feeds on the seeds and cones of the Mexican pinyon and the ponderosa pine when they are available, but will also take fungi, buds, bark, and carrion. Breeding normally occurs in summer, with a spherical nest being built high in the canopy.

## Appearance

These unusual animals usually inhabit areas, dominated by Ponderosa pine trees that provide them with required nutrients. Abert's squirrels are identified by their long tufted ears, due to which the animals are sometimes called 'tassel-eared squirrels'. These mammals exhibit the ear tufts during most of the year. Mature individuals lose these tufts between July and September. Abert's squirrels have no fear of heights. When foraging, these animals are frequently observed moving between branches high in trees.

## Distribution

Abert's squirrels are distributed throughout the southwestern United States and the north central Mexico, where these animals occur in scattered populations. Thus, the United States hold 4 isolated populations of this species, two of which are considerably large, while the other two are small. In Mexico, Abert's squirrels are presented by two large but isolated populations. The ideal habitat of this species is mountainous areas, dominated by ponderosa pine tree. In the past, Abert's squirrels were mistakenly thought to be dependent on this tree. In fact, they just rely heavily on it.

## Behavior

Abert’s squirrels do not appear to be territorial. Usually, multiple individuals may share the same nest. Meanwhile, each individual can use more than a single nest. They are diurnal. Active period of the day starts just before sunrise, lasting until just before sunset. Living among ponderosa trees, these animals occur in large concentrations of 2 - 114 squirrels per square kilometer. They are solitary foragers, spending their daytime hours looking for food. No information is available on whether they have any hibernation or torpor habits. In the beginning of the breeding season, which occurs in spring months, these squirrels display a highly social behavior. During the rest of the year, they are typically less social. Abert's squirrels communicate with conspecifics through vocal, visual, touch, smell and taste. Vocalizations include characteristic high-pitched clucks, barks, screeches and squeals, which are easily distinguished from these of other squirrels.

## Diet

Abert's squirrels are herbivores, they primarily feed upon certain parts of the ponderosa pine: during the warm season of the year, they consume seeds and buds of this tree, whereas the winter diet typically consists of the inner bark of the ponderosa pine. They are also known to supplement their usual diet with occasional mistletoe and fungi.

## Reproduction

Abert’s squirrels are polygynandrous (promiscuous): this is when both males and females have multiple mates. During the mating season, males display aggressive behavior towards each other. A pack of males can follow a female through the forest for about 11 hours by day, led by the dominant male. Abert’s squirrels mate between late February and early June. Gestation period lasts for 43 days, yielding 1 - 5 babies with an average of 3 per litter. Newborn squirrels lack fur and come with closed eyes. Males of this species display no parental care except for guarding their mates after mating. At 7 weeks old, the young begin climbing down to the ground. Weaning occurs after 10 weeks old, whereas sexual maturity is reached by 11 months old.

## Population

### Population threats

In spite of being classified as Least Concern, this species is threatened by living in isolated populations, depending on the distribution of ponderosa pine. Another notable concern is habitat destruction by clear-cutting throughout large areas of their natural range.

### Population number

According to IUCN, the Abert’s squirrel is widely distributed and abundant at some localities but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) and its numbers remain stable.

### Ecological niche

Due to relying on the ponderosa pines, these animals have hugely affected this tree, which is their main source of food and shelter. On the other hand, they have negatively affected Mount Graham red squirrels, inhabiting the Pinaleño Mountains (Arizona): Abert's squirrels were introduced to the habitat of endangered red squirrels, which consequently led to a harsh resource competition between these two species.

## Fun Facts for Kids

Squirrels are highly intelligent animals. Moreover, they are known to be extremely adaptable and acrobatic creatures. For example, hanging a bird feeder in your garden, you will definitely have to struggle with squirrels of the area.

These animals accumulate extra weight, which helps them keep warm during the winter.

The word 'squirrel' originates from Greek and means ‘shadow tail’.

The hind limbs of squirrels are extremely flexible, allowing them to quickly and easily climb up and down, when moving in trees.

They have five toes on their hind legs and four - on the forelegs. The toes on the hind feet are very sharp, helping them grip tree bark with ease when climbing.

Squirrels are presented by as many as 285 species around the globe, except for Antarctica and Australia.