Endangered species conservation never looked so cute
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DENVER — Born at almost six feet and 170 pounds, endangered reticulated giraffe calf Thorn already towers over the animal care specialists who care for him at the Denver Zoo Conservation Alliance.
But his preference for thinly chopped carrots and his tendency to plop down on his way to the feeding platform betray his age. At two months old, Thorn is one of the newest baby animals born at the Denver Zoo Conservation Alliance, or DZCA.
Whether they are eventually released into the wild to help recover their species population or remain in captivity to contribute to research and observation, the baby animals born in zoos play an important role in conservation.
In the past 20 years, DZCA has seen more than 3,000 births, representing 258 species of amphibians, birds, mammals and reptiles, though not including fish or invertebrates.
Thorn is the first calf born to the zoo’s current giraffe breeding pair, BB (mom) and Jasiri (dad).
He is the first giraffe born at the zoo since 2017, when a female giraffe on birth control surprised zoo staff by giving birth to now eight-year-old Dobby.
Zoo staff refer to Dobby as Thorn’s “uncle.” Though they share no relation, the pair are almost inseparable.
Dobby’s premature, surprise birth is not the norm for zoos. BB’s carefully monitored, 444-day pregnancy with Thorn is more standard.
The animal births at DZCA are not random. The zoo is part of the Association of Zoos and Aquariums, a partnership of about 250 facilities around the world. Through this partnership, species experts map out Species Survival Plans, or SSPs, to determine when and where zoo animals should breed.
Participating zoos and aquariums provide information about the animals they house, including their ancestry, which the SSPs take into consideration.
“They're looking at everything from who has the capacity to work with these species, who has the knowledge base to work with these species, genetics, compatibility, relationships [and] social groups,” said Emily Insalaco, senior director of wildlife care and ecology at DZCA.
“From there, we put together a full plan of which animals are where, which animals should breed, which animals shouldn't breed, who can hold on to animals [and] how do we learn more about them.”
SSPs publish breeding and transfer plans every two or three years. (The transfer element comes into play when animals selected for breeding need to be moved from one facility to another.)
When DZCA is designated as an institution where a birth should take place, the zoo works to get the breeding pair together and pregnant.
Insalaco said ideally, the zoo sets up a natural social group for the breeding pair to interact and become pregnant on their own. But she’s seen a lot of instances where animals need help conceiving, in which case the zoo uses artificial insemination to start the pregnancy.
For example, the zoo welcomed its first greater one-horned rhino calf, Joona, in 2020 after 12 rounds of artificial insemination.
After the babies are born, the zoo’s animal caretakers prefer to take a backseat when it comes to parenting.
“Our first choice usually is to let the parents do the work. They're much better at raising their own babies than we are,” Insalaco said. “But sometimes we do need to step in and assist a little bit. That can look like anything from maybe a little bit of rearing with a bottle while they're figuring things out, all the way to hand-raising.”
Hand-raising refers to animal care specialists fully taking over the nursing of a baby animal.
Some researchers and animal rights activists have criticized zoos’ intervention into animals’ breeding habits.
A 2016 study on the effect of hand-raising on large cats — Siberian tigers, snow leopards, cheetahs — found some species of hand-raised large cats had higher infant mortality rates and produced fewer offspring later in life. (That same study found some species had lower infant mortality rates and gave birth to larger litters.)
In 2022, a study on female giant pandas found those who were artificially inseminated had higher rates of cub rejection than pandas who became pregnant naturally.
Whether or not the parents need assistance raising their baby, the caretakers will interact with the new arrival so it becomes comfortable with zoo staff.
This familiarity helps the animal care specialists train the animals to cooperate during medical examinations, vaccinations, measurements and other interactions.
At five months old, Aster, the first Somali wild ass foal born at DZCA, is getting more comfortable taking food from caretakers, so they’ve started training her.
The Somali wild ass is one of the rarest animals at DZCA. Fewer than 600 remain in the wild, making it a critically endangered species.
Daisy gave birth to Aster in January. Aster will be fully weaned off her mother when she is about 11 months old.
The zoo welcomed its first red-necked wallaby joey, an unnamed male, in September, born to first-time parents Adelaide and Cricket. The following month, another wallaby, Lachlan, gave birth to the first joey’s half-sibling, whose sex is still unknown.
The exact birthdays of these babies is hard to tell. After 29 days of gestation, a joey is born into its mother’s pouch, where it will stay developing and nursing for another nine months. After about five or six months, a joey will start peeking its head out of the pouch.
Unless the animal caretakers see the mother wallaby giving birth, they can only estimate the baby’s exact age based on how much fur they can see and when the baby starts peeking out from the pouch.
These observations would be even more difficult to make on wallabies in the wild, who aren’t trained to approach caretakers offering snacks.
Insalaco said the information that zoo staff gather through observations and up-close interactions is a helpful tool for researchers assessing the same species in the wild. Caretakers can learn even more about a species when they can follow their life from the beginning, another reason animals born in zoos are so important for conservation.
Animal care staff take note of breeding behavior, length of pregnancy and what a healthy birth looks like. After birth, they take measurements and create birth curves, plotting what healthy growth for each species looks like.
The length of time that an animal is considered a baby varies widely depending on the species. Two-month-old Thorn will be considered an adult when he reaches four or five years old.
Meanwhile, the almost two-year-old Sumatran orangutan baby is on a slower timeline; she’ll be mature around 8 to 10 years old.
The care taken to raise the zoo’s “little” ones continues long after they’re not so little anymore.
“Having babies is a great way for us to connect with our guests. Everyone loves to come and meet new arrivals to the zoo, and they definitely help us make a special connection,” Insalaco said.
“But any time that we're caring for our animals, we're looking at their entire life stage. We're looking at them from birth through their adulthood, all the way through their geriatric care. It's important to us that we're able to connect with those animals as caretakers and to learn and help them thrive through every aspect of their life.”
Type of story: News
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources.
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources.
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