In animal news this week, researchers announced that 25 primate species on three continents are "on the brink of extinction and need global action to protect them from increasing deforestation and illegal trafficking," reported the Associated Press. The report from the International Union for Conservation of Nature lists species of spider monkeys, lemurs, gorillas and other primates as severely threatened.

Some positive news came out of Colorado this week, when it was reported that "Stumpy," the three-legged tortoise was safely returned to his owner. Stumpy was "kidnapped" when "Wildman" Phil Rakoci's car was stolen from a Walmart parking lot in Englewood, Colorado. The tortoise, who uses a wheel to scoot around, "loves people," according to Rakoci. Stumpy, along with other creatures like a python and several tarantulas, are part of a traveling educational show for children.

A keeper at Sydney's Taronga Zoo was critically injured this week when an elephant calf crushed her against a fence post. AP reported that the woman was in "critical but stable" condition at Sydney hospital.

Scientists revealed this week that dolphins sleep with only half of their brains, while the other half remains alert and on the lookout for sharks. A marine biologist at the National Marine Mammal Foundation in San Diego told LiveScience, "Dolphins can continue to swim and think for days without rest or sleep, possibly indefinitely."

In case you missed International Sloth Day on October 20, check out some of the best videos of one of the cutest animals around.

Below, find some of our favorite animal photos taken in the past week:

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  • A chevrotain or mouse deer walks in its enclosure at Zurich Zoo, Zurich, Switzerland, Wednesday, Oct. 17, 2012. (AP Photo/Keystone/Patrick B. Kraemer)

  • In this Oct. 15, 2012 photo provided by the Lincoln Park Zoo in Chicago, a newborn western lowland gorilla, born on Oct. 11, cuddles with its mother Bana, 17, at the zoo. The baby has yet to be sexed or named and appears to be doing well. Zookeepers and vets will closely monitor Bana and her baby to ensure they continue to do well, as the first few weeks are critical in the survival of newborn gorillas. (AP Photo/Courtesy of the Lincoln Park Zoo, Tony Gnau)

  • In this photo made Monday, Oct. 15, 2012, and provided by the Cincinnati Zoo, a baby giraffe stands next to it's mother at the zoo. Zoo officials say they got more than 5,000 submissions as part of a contest to name the baby giraffe, born Oct. 12. (AP Photo/The Cincinnati Zoo, David Jenike)

  • A red lionfish (Pterois volitans) swims in the aquarium of the Schonbrunn zoo in the gardens of the Schoenbrunn Palace in Vienna on October 16, 2012. The red lionfish is a venomous coral reef fish. AFP PHOTO / ALEXANDER KLEIN

  • Sheep are pictured at the Kirkjubour village on the Streymoy Island as a rainbow appears between the Hestur (L) and the Koltur (R) islands on October 16, 2012, Faroe Islands. The Faroe Islands are known for its fishing and sheep farming as the main industries. AFP PHOTO / JONATHAN NACKSTRAND

  • Yellow tang fishes (zebrasoma flavescens) and other fish species swim in the aquarium of the Schoenbrunn zoo in the gardens of the Schoenbrunn Palace in Vienna, Austria on October 16, 2012. AFP PHOTO / ALEXANDER KLEIN

  • This image provided by the San Diego Zoo shows the zoo's 11-week-old giant panda cub taking his first steps during a veterinay examination Thursday Oct. 18, 2012 in San Diego. The unnamed male cub is the sixth giant panda born at the San Diego Zoo. (AP Photo/San Diego Zoo, Ken Bohn)

  • A Sand Goanna also called Gould's monitor (Varanus gouldii) is seen in the Schonbrunn zoo in the gardens of the Schoenbrunn Palace in Vienna on October 16, 2012. Goannas stick out their forked tongues when hunting and searching for olfactory clues. AFP PHOTO / ALEXANDER KLEIN

  • Panda Fu Hu (R) eats bamboo at the Schoenbrunn zoo in Vienna, Austria on October 16, 2012. Fu Hu will be transported to China in November 2012. AFP PHOTO / ALEXANDER KLEIN

  • Six-month-old arctic foxes look out from their enclosure at the Stone Zoo in Stoneham, Mass. Thursday, Oct. 18, 2012. (AP Photo/Elise Amendola)

  • A six-month-old arctic fox yawns while napping with his littermate in their enclosure at the Stone Zoo in Stoneham, Mass. Thursday, Oct. 18, 2012. (AP Photo/Elise Amendola)

  • In this photograph released by DHL via AP Images on Thursday, Oct. 18, 2012, Jae-Jae, a male Sumatran tiger, has been transported by DHL from Akron Zoo, Ohio, USA to ZSL London Zoo, UK. Melati, a female tiger from Perth Zoo, Australia, was also transported by DHL a few weeks earlier. With fewer than 300 Sumatran tigers now in the wild, ZSL London Zoo is hoping to breed the tigers as part of a wider conservation program. (Jay LaPrete/AP Images for DHL)

  • Turkey fish swim in an aquarium in the zoo of Frankfurt, Germany, Tuesday, Oct. 16, 2012. (AP Photo/Michael Probst)

  • Pacific moon jellyfishes (aurelia labiata) swim in the aquarium of the Schonbrunn zoo in the gardens of the Schoenbrunn Palace in Vienna on October 16, 2012. AFP PHOTO / ALEXANDER KLEIN

  • A seahorse swims in an aquarium in the zoo of Frankfurt, Germany, Tuesday, Oct. 16, 2012.(AP Photo/Michael Probst)

  • NEW YORK, NY - OCTOBER 20: French Bulldog Enzo poses as a lobster at the Tompkins Square Halloween Dog Parade on October 20, 2012 in New York City. Hundreds of dog owners festooned their pets for the annual event, the largest of its kind in the United States. (Photo by John Moore/Getty Images)

  • NEW YORK, NY - OCTOBER 20: Little, a chihuahua, and Pants pose as a pirate and a devil at the Tompkins Square Halloween Dog Parade on October 20, 2012 in New York City. Hundreds of dog owners festooned their pets for the annual event, the largest of its kind in the United States. (Photo by John Moore/Getty Images)

  • NEW YORK, NY - OCTOBER 20: Harry, a corgi, poses as a fire truck at the Tompkins Square Halloween Dog Parade on October 20, 2012 in New York City. Hundreds of dog owners festooned their pets for the annual event, the largest of its kind in the United States. (Photo by John Moore/Getty Images)

  • Perth International - Day 4

    PERTH, AUSTRALIA - OCTOBER 21: A kangaroo is pictured on the 15th fairway as Jason Dufner of the USA waits to take his second shot during round four of the Perth International at Lake Karrinyup Country Club on October 21, 2012 in Perth, Australia. (Photo by Paul Kane/Getty Images)

  • SEA ISLAND, GA - OCTOBER 19: A dragonfly is seen on the 10th hole during the second round of The McGladrey Classic at Sea Island's Seaside Course on October 19, 2012 in Sea Island, Georgia. (Photo by Sam Greenwood/Getty Images)

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