(Courtesy Chicago Zoological Society)

A set of proteins long used to evaluate the well-being of humans can also serve as a marker for the welfare of animals in zoos and aquariums, according to a new study. 

(Courtesy Chicago Zoological Society)

The latest member of Brookfield Zoo’s four-generation family of western lowland gorillas was born June 1, the third offspring of Koola, the newborn’s 23-year-old mother. 

An African burrowing scorpion is among the highlights of Brookfield Zoo’s new “Amazing Arachnids” exhibit. (Jim Schulz / Chicago Zoological Society)

Get a close-up look at 100 live eight-legged critters – aka arachnids – including spiders, scorpions, tarantulas and more at Brookfield Zoo.

Michelle Soszynski, a senior veterinary technician at Brookfield Zoo, monitors Layla, a 7.5-year-old eastern black rhinoceros, as she receives a CT scan inside Brookfield Zoo’s Pachyderm House. (Jim Schulz / Chicago Zoological Society)

Following a historic diagnostic procedure last month, Layla, a 2,300-pound eastern black rhinoceros, underwent life-saving surgery last week to relieve an infection.

(Courtesy Chicago Zoological Society)

Hoping to identify the source of an infection, veterinarians performed what is thought to be the first ever CT scan on a rhinoceros.

(Courtesy Chicago Zoological Society)

The 50-year-old gorilla was the zoo’s oldest animal. “Knowing it’s the right decision doesn’t make it hurt any less,” said Amy Roberts, curator of mammals for the Chicago Zoological Society.

(Jim Schulz / Chicago Zoological Society)

One year after welcoming its first baby reindeer in nearly four decades, Brookfield Zoo added another newborn fawn this week.

(Jim Schulz / Chicago Zoological Society)

The yet-to-be-named chick is healthy and being hand-reared by animal care staff, the zoo said this week.

(Jim Schulz / Chicago Zoological Society)

St. Patrick’s Day festivities kicked off a day early at Brookfield Zoo last week, where seals, camels, lemurs, orangutans and gorillas got shamrock-shaped and green-colored treats.

Nora, a 4-year-old western lowland gorilla, eats a heart-shaped treat at Brookfield Zoo. (Jim Schulz / Chicago Zoological Society)

Date or no date, single or taken, animals at Brookfield Zoo experienced Valentine’s Day with the best kind of gift: food.

Chicago Zoological Society’s veterinary staff perform an emergency appendectomy on Ben, a 40-year-old orangutan at Brookfield Zoo. (Jim Schulz/Chicago Zoological Society)

Ben, a 40-year-old orangutan at Brookfield Zoo, underwent an emergency appendectomy last month after veterinary staff discovered a ruptured appendix. 

Brookfield Zoo veterinary staff monitor Zana, a 5-year-old Mexican wolf, during an artifical insemination procedure Feb. 4. (Courtesy Chicago Zoological Society)

Nearly 30 years ago, scientists began collecting semen samples from Mexican wolves. On Sunday, Brookfield Zoo artificially inseminated one wolf as part of an effort to boost the genetic health of the endangered species. 

Ramar, a 50-year-old western lowland gorilla, is the oldest animal at Brookfield Zoo. (Courtesy of Chicago Zoological Society)

Ramar, one of the oldest gorillas in the country, celebrated a milestone birthday this month with a frozen “cake” filled with fruit and raisins. 

A male gray seal was born at Brookfield Zoo on Dec. 26. (Jim Schulz / Chicago Zoological Society)

Brookfield Zoo welcomed a newborn gray seal on Dec. 26. The male pup weighed 36 pounds at birth and is expected to weigh more than 120 pounds by the time he is weaned at three weeks. 

Four specially-designed suction cups are used to attach a bio-logging device to the backs of bottlenose dolphins at Brookfield Zoo. (Alex Ruppenthal / Chicago Tonight)

Brookfield Zoo is leading a first-of-its-kind study to collect data from dolphins and other aquatic mammals using a Fitbit-like device that figures to revolutionize human understanding of the animals’ behavior.

(Courtesy Chicago Zoological Society)

From siblings with snowballs to wrestling chimpanzees, playful behavior is usually easy to spot. But the question of why we play – and whether we all play for the same reasons – is less apparent.