Mad about Science: Animal babies

By Brenden Bobby
Reader Columnist

Human beings spend a lot of time caring for their young. As a species, we officially consider our children to become adults at 18 years of age, when they can theoretically take care of themselves in the world. This age varies quite dramatically in the animal kingdom.

Humans care for younger humans for such an extended period of time for many reasons. Despite becoming capable of reproduction during puberty — the mark of adulthood throughout much of the animal kingdom — humans continue to care for their young into adulthood due to the amount of time it takes for our brains to critically develop. 

A cow elk and calf. Courtesy photo.

The age at which this happens is believed to be somewhere in the mid-to-late 20s, but 18 was where society decided to land as a happy medium. After all, a human can’t fully develop into a rich and complex person until they’ve had some life experiences and mistakes, and 18 has provided enough time for the absorption of functional knowledge and practical experience to generally keep oneself safe and alive for at least another 15 years.

This long experience of childhood is linked to the high level of human brain development. Absorption of knowledge is an energy intensive process, which no other animal experiences in the same way as humans. We need to learn how to read, write and express ourselves through art, song and language. Humans need to understand how to decode problems in the universe through the use of math and how to utilize tools to create environments for ourselves in ways other animals don’t.

The energy expended to bring an animal to adulthood is directly linked to the amount of time a mother in the wild will spend with her young. The larger or more intelligent the animal, the longer it will spend time being raised by its mother.

It should come as no surprise that primates spend a lot of time raising their young. Chimpanzees form lifelong bonds with one another and will even care for their aging mothers as time passes, creating a cyclical pattern that is reminiscent of some humans who care for their aged family members.

Gorillas share a similar gestational period to humans — between eight and nine months — and will care for their young for up to four years after birth. Orangutans may continue to nurse and raise their young for up to six years, which can be up to 20% of an orangutan’s life.

African elephants have the longest pregnancy of any land animal at 22 months. Baby elephants are born blind and completely helpless and rely on their mothers for everything. Mother elephants will nurse their young for up to six years and will accept help with mothering from other females in their herd. Male elephants will leave to spread their genes with other elephant herds between 9 and 18 years old.

The life of exotic animals probably isn’t very relevant to your day-to-day affairs. Closer to home, the North American elk (Cervus elaphus, Cervus canadensis or wapiti, depending on who you ask), are currently at the beginning stages of rearing their calves. Elk give birth in May and early June, roughly 250 days after the rut in the prior fall. During the rut, bull elk compete over harems of cows by bugling and fighting for dominance and the opportunity to spread their genes through reproduction. This is also the time when humans prey on elk.

Calves born around this time generally weigh a little more than 30 pounds at birth. They are born spotted and completely scentless to mask them from predators. Cows will leave their herd in order to give birth, returning to the herd with their calves after more than two weeks. A calf may nurse for up to five months, though it will be eating grass by a month old. Young elk will leave their mother’s side once the mother is ready to give birth to new calves the following year. 

A sexually mature cow will begin breeding after one year, while bulls will be ready at 2 years old. Males generally won’t have the opportunity to outcompete other males to reproduce until they’re at least 5, and by 11 years old won’t be capable of claiming their own harem. The average lifespan of elk is 12 years.

Mountain lions are much harsher mothers than their herbivorous prey. Female mountain lions reproduce every two years and may have litters of up to six cubs. They will nurse their young for seven weeks, at which point they will cut off their young and teach them how to hunt. 

Despite their tough love, female mountain lions often spend as much as 75% of their lives devoted to their generations of cubs. Around the time a litter is ready to strike out on their own, the mother may be ready to reproduce or even already pregnant with another litter. 

Mountain lions are very solitary and will mark their territory in a manner similar to a house cat: through smell and scratching. Finding a pile of feces that smells strongly of cat urine denotes that you have entered a mountain lion’s domain and should proceed with caution — chances are, the cougar will see you and watch you well before you’ve even discovered the scent mound.

Another animal in our backyard is the osprey. Ospreys will lay their eggs in April with each egg being laid roughly three days apart from each other. The parents will incubate the eggs for four to five weeks until they hatch and spend the next two months caring for their young. By September, the mother will have begun to migrate to warmer climes while the father will remain behind to continue training the offspring how to fish for themselves. Generally, the father will migrate with the young a few weeks after the mother.

Stay curious, 7B.