A baby hippopotamus lies next to its mother on the first day it was presented to the public at the Zoo Berlin zoo on November 1, 2011 in Berlin, Germany. The baby hippo was born at the zoo on October 23. (Photo by Sean Gallup/Getty Images)

Radin the Sunda pangolin hitches a ride on Nita as their keeper looks on. The elusive and nocturnal Sunda pangolin produces only one or two offspring a year and Radin is the third pangolin baby born in Night Safari since 2011. (Photo by Wildlife Reserves Singapore)

“Happy Feet” the emperor penguin that washed up on the Kapiti Coast last week, undergoes a medical examination at Wellington Zoo on June 29, 2011 in Wellington, New Zealand. The young penguin landed on NZ shores last week, after traveling over 3,000 kilometres from the antarctic. The ill penguin was operated on at Wellington Zoo several times this week to remove sand and sticks from it's stomach with hopes it will recover fully. A team of experts is likely to decide today, whether the bird will remain in captivity in New Zealand, or be transported back the the antarctic. (Photo by Hagen Hopkins/Getty Images)

A Sumatran Tiger tears apart a wrapped Christmas present at Taronga Zoo on December 21, 2011 in Sydney, Australia. Animals received Christmas themed enrichment foods as part of the Zoo's regular program to encourage the animals to forage for food and help improve hunting abilities. (Photo by Brendon Thorne/Getty Images)

A Sumatran Tiger looks at visiting children from it's enclosure during the ZSL London Zoo's annual stocktake of animals on January 5, 2015 in London, England. The zoo's annual stocktake requires keepers to check on the numbers of every one of the 800 different animal species, including every invertebrate, bird, fish, mammal, reptile, and amphibian. (Photo by Dan Kitwood/Getty Images)

Sumatran tiger Jumilah is seen with one of her cubs on display at Taronga Zoo on October 25, 2011 in Sydney, Australia. The Sumatran tiger cubs, born in August to mother Jumilah, will meet the public for the first time this week. (Photo by Mark Kolbe/Getty Images)

Zookeepers measure the length of a pueblan milk snake in the Reptile House of ZSL London Zoo as part of their annual weighing and measuring of their animals on August 25, 2011 in London, England. The heights and weights of over 750 different animal species at the zoo are recorded into the International Species Information System, to monitor their health and share the data with other zoos across the world. (Photo by Oli Scarff/Getty Images)