A 14-year-old otter is not its usual, energetic self; staff at the New York Aquarium move their sharks to a new exhibit; quirky capercaillies need help producing healthy chicks.

Crate training Nikita the Amur tiger in preparation for her move to Washington, D.C., proves challenging; an endangered Chinese alligator shows signs of being pregnant; staff prepare to release rare New England cottontail rabbits into the wild.

A trio of new penguin chicks are introduced to the pool for their first swim; family dynamics change when the mandrill monkey troop welcomes a new baby; a pair of king vultures are prepped for their big debut at the Queens Zoo.

Peaches, a 2-month-old warthog, charms his keepers while training to become an animal ambassador; a nervous one-horned rhino adjusts to her new exhibit; Willow, a red panda, shows signs of being pregnant.

Keepers introduce three gaur, a large species of cattle, to the rest of the herd; a sickly sambar fawn is rushed to the health center; the bird department prepares for the arrival of great hornbills.

Iray, a red ruffed lemur, is rushed to the health center when keepers discover a wound on its leg; a new exhibit is built for the Pallas' cats, the original grumpy cats; seven baby turtles join the zoo's colony of an endangered species.

A giraffe named Mashengo journeys from the Indiana Zoo to his new home in the Bronx; keepers hand-raise endangered ducklings and release them at the Central Park Children's Zoo; love is in the air for a pair of cloud rats.

Cardiologists try to determine why the geladas are experiencing a life-threatening heart condition; Nile crocodiles are shifted off exhibit for a maintenance project; the elephant shrews are breeding.

A team tests the problem-solving skills of lions against those of snow leopards; Willow, a young red panda, is having mysterious foot problems; the bird department awaits the gender reveal of two new adjutant stork chicks.

A new bison calf has a hard time keeping up with his mom; the bird department prepares a group of Von der Decken hornbill chicks for their move to the Minnesota Zoo; keepers at the Central Park Zoo hope the female snow monkeys accept a new male.

Max the camel faces new challenges as he ages. The zoo prepares to give an injured turkey vulture a permanent home, but after healing, there may be a change of plan. Willow the red panda gives birth to two baby cubs.

A charismatic ostrich named Olga works to be reunited with her flock. Buster the squirrel monkey is introduced to the Zoo's troop of feisty females. A functionally extinct species of turtle finds new life and everyone's favorite warthog is back.

The zoo anxiously awaits the arrival of a snow leopard called K2's fourth cub. The staff is pleased when a pair of Andean condors embrace their new enclosure, while a squirmy binturong fights his annual vaccination.

A rowdy, young markhor is injured and vets must treat his infected hoof. The TAB staff head to Manhattan to rescue a wallaby living in an apartment, while a fruit bat discovers how to spread her wings, and a trio of alligators move into their summer home.

A trio of abandoned puma cubs arrives at the zoo, while the staff grows concerned that Ella, the oldest rhino, is not acting herself. Meanwhile, a Caribbean flamingo is born at the zoo after nearly two decades, and Otto the stallion makes his debut.

An okapi called Magani is ready to breed and is paired with veteran Kweli to learn the ropes. Lola the blue iguana plays hard-to-get when introduced to a potential mate, and anteater Velcro shows off her talents with a new tool.

A popular sea lion falls ill after ingesting a foreign object. The avian team devises a plan to increase the cock-of-the-rocks population. Endangered snakes are coupled for breeding, and Andean bear cubs meet their fans.

Two sickly newborn fawns form an unbreakable bond while they are hand-reared by staff. Leopard Khazo gets a surprise that enhances her life, and tensions run high as the reptile staff attempts to collect blood from Cuban crocs.

The zoo opens an endangered turtle species facility, while Malayan tigers Suhanna and Rimba struggle to breed, because Rimba seems disinterested. Needles the porcupine gets a new mate, and the Guar herd eagerly await the arrival of new calves.

It's a series of firsts when the Central Park Zoo welcomes its first-ever Atlantic puffin chick. A rhino called Penny undergoes a series of allergy tests, while an endangered species of gecko welcomes her first hatchling.

Seven "Little Blues" join the penguin exhibit and are quick to mingle with the rest of the colony. When a honey-loving grizzly slows her step, the staff grows concerned. A turtle can't seem to get along with the alligators, and a nyala calf is born.

After more than 100 venomous snakes are taken from a private home, it's up to the zoo to care for them. Two Pronghorn fawns make their debut, but problems arise that have keepers concerned, while a device is built for a Red River hog needing a challenge.

A trio of rare Dhole canines are prepared to make their cross-country journey to the zoo, and keepers anxiously await their arrival. A tinamou chick must be hand-reared, while a specialized tool is welded to extract a tusk from a charming Babirusa.

The Zoo takes audiences on a first-ever, in-depth look behind the scenes at the Bronx Zoo. With full access to its 265-acre campus, located just 10 miles from Times Square, we shine a light on a world of more than 6,000 animals and the 500-plus people who care for them.

The zoo's medical team must perform critical surgery on a bison calf born with a bowed leg; three lynx kittens are ready to explore their exhibit