Have you ever been slightly abashed when you assume someone’s age and then find out that either wow…. they are waaayyy older than you thought, or dear goodness, this person is a baby?! Determining age in humans just by sight can be really challenging! Determining squirrel age and the ages of other wildlife, on the other hand, is much easier! With wild animals we can look at them and gauge their age based on development and growth!
In the human world, age really doesn’t matter for the most part once we hit certain milestones. In the wildlife world though, age can play a factor in how they interact with the ecosystems they live in. Baby dragonflies (nymphs) live in water, whereas adult dragonflies live on land. This completely changes their diets and adaptations! Another example is octopuses. For females, generally around their 3rd birthday they lay their own eggs. This triggers senility and degradation of their brain as they care for the eggs. Knowing the age of an octopus can help veterinarians and marine biologists identify potential health issues.
Age doesn’t matter for just insects or marine species. As mammals age and develop they may have their own unique adaptations and skills that they get along with age. Their teeth may change and their behaviors may differ. Their fur colors may transition and how they live (either socially or independently), may change as well. This kind of sounds like humans, right? Developmentally, we might start walking around, lose our first baby teeth, or hit puberty generally around similar ages, but personal growth varies greatly! When we land a career, find a significant other, have children, move to a new place, etc… all happen at vastly different rates.
There’s nothing wrong with humans growing and experiencing life at different rates, but for wildlife, life comes and goes in a fairly straightforward manner. Let’s take a look at one such species: the squirrel!
Eastern Grey Squirrels in the wild usually live to be roughly 2 years old. At birth, their chances of survival aren’t very high, but if they can actually make it to adulthood, their life expectancy can increase to 4-6 years old! In fact, the oldest Eastern Grey Squirrel in the wild was recorded to be 12 years old. Incredible! Predation in younger squirrels is quite high, which is what threatens the baby’s life expectancy the most. Once they mature, they have adaptations to help them avoid predation.
When a baby is born, it takes roughly 8-10 weeks for it to be grown enough to survive without their mother’s care. The next spring or summer season after they were born, they reach sexual maturity and have their own litters.
Squirrels have very obvious milestones as they age. When they are born, they are little, weighing about a half ounce, pink, and hairless. Their eyes are closed and they need their mother’s care and warmth constantly! At 1 week old, they are still hairless and blind, yet they are now looking a little more grey, rather than pink along their backs. When they reach 2 weeks, they appear to have a 5 o’clock shadow or peach fuzz of fur and are now over an ounce in weight! At 3 weeks, they have a thin layer of fuzz and their skinny tails now have greyish-silver fur. Even at 4 weeks, when the squirrels have over doubled in size and have an obvious “squirrel-like appearance” with their grey fur along their backs, white tummies, and bushy tails, they are still blind.
Finally, at 5 weeks old they have finally opened their eyes and are ready to play! It’s amazing how much movement and jumping you can do if you can see! The mothers do not need to constantly watch over and warm the babies and she teaches them how to navigate tree branches and jump around. At 6 weeks old, the tail gets noticeably bushier and they now look like miniature adults. At 7 weeks old, the baby squirrel (similarly to human teens) starts to behave like an adult and tries to feed itself, jump around, and explore the world, although they still need the attention of the mother!
Finally, at 8 weeks old, they don’t need mom to provide food with them and she has taught them how to escape predators. They leave the nest a few days later and attempt to successfully find their way in the world!
Being able to recognize wildlife by their age can help humans understand their care and point of growth and development when our paths cross. Squirrel nests can fall out of trees during storms, babies who are learning to jump can lose balance and fallen, or squirrels get injured by cars or predators. Just because a squirrel looks like it needs help though, doesn’t mean it needs help from a rehabilitation center! It could just need help from it’s mom, who might be nearby.
If you find baby squirrels and have a bit of time to observe and make sure the mom returns, try to play (using this YouTube Video) recordings of baby squirrels crying. While the babies are still young, the mothers know that they can’t wander too far from the nest and will hear the crying sound. She’ll come running and can help care for fallen babies.
Babies that have their eyes open are able to survive a little longer without mom. Try to find the nest to return them to, or if you can’t, put them in a shoebox with some warm blankets and leaves until the mom returns. Try to play the recording again, just be aware that the mom may have further to travel to get them and it may take a half hour – hour for her to find them.
First of all, thank you for caring about these fuzzy acrobats of the mammal world! They are important members of the ecosystem, even if they do happen to steal your birdseed.
Showcase your love of squirrels by bringing them home (although not from the wild – that’s illegal), by shopping with The Art of Ecology.