Blog: Center for the Science of Animal Care and Welfare

All the Right Moves- What It Takes to Transfer Animals Among Zoos

A binturong departs Brookfield Zoo for Boise. A gorilla comes to us from Chicago’s North Side (Lincoln Park Zoo). Wolf cubs prepare for a new life in Arizona.


In 2016, more than 4,000 animals transferred to or from Brookfield Zoo. Each of these animal moves—from the tiniest dart poison frog to a 600-pound tiger—is based on careful strategy and involves meticulous preparation and planning.

When we transfer an animal to another institution, we make sure the animal is healthy and, if young, is weaned. We provide the other institution with complete medical and behavioral records for the animal and may even send along a supply of its food to make the transition easier. Based upon breeding season and weather, we determine the best time of year for the transfer to take place.

Animal welfare before, during, and after transport is of the utmost importance to us. As every pet owner can attest, even under the best circumstances, travel can be eventful for animals. Digestive systems often may be temporarily disrupted, so one type of preparation might be to begin a course of probiotics to bolster stomach health prior to the transfer.

Most zoo-to-zoo trips are by land, so we may begin behavioral modifications to prepare for the trip, such as training animals to enter a trailer. We also maintain a group of trusted animal movers, professionals who understand and are dedicated to caring for our precious cargo. In some cases, members of our own animal care staff accompany our transferee on the trip.

Upon arrival at the receiving zoo, the animal is placed in quarantine—in most cases for 30 days—and if dietary changes are needed, they are made incrementally to be less disruptive to the animal.

Brookfield Zoo animals arrive and depart for four primary reasons:
1. To bolster the diversity of the animal collection for guests.
2. To support national or international breeding programs.
3. To improve genetic pairings of animals or create populations with sound demographic structures.
4. To potentially aid in reintroducing animals back into the wild.
Preserving Threatened Species
The Chicago Zoological Society participates in 113 Species Survival Plans (SSPs) of the Association of Zoos and Aquariums (AZA). Based on data from conservationists around the world, experts at AZA determine which species are most imperiled in the wild and can best be safeguarded through zoo breeding programs that increase populations in managed settings.

Once an SSP is established, a zoo accredited by AZA can decide if it wants a species and then join the SSP. The goal is to maintain genetic diversity and demographic stability, such as the male-to-female ratio, of each species.

With 232 institutions in North America accredited by AZA—each with dozens or hundreds of species and often thousands of animals—you can imagine how incredibly complicated it is to keep track of all this. AZA must determine which zoos participating in an SSP have which individual animals; analyze the animals’ reproductive capacity, age, and sex; calculate all of the genetic relationships from ancestry; and much more.

Fortunately, there’s software that makes this analysis much easier, and one of the Society’s conservationists, population geneticist Dr. Robert Lacy, helped develop it. PMx analyzes a population from genetic and demographic standpoints to run through pairing scenarios.
Each SSP has a manager, as well as a studbook keeper who maintains a “studbook,” a record of all the movement, breeding, births, and deaths of a species. Society staff manage 15 SSPs, including for gray seals and snowy owls, and the studbooks for 16 species, such as binturongs and Jamaican boas. These two are in charge of making a recommendation on a transfer. Once they do, institutions are encouraged to provide feedback on a number of variables.

Perhaps the behavior of one herd member would make it difficult for a new animal to easily adjust. Or maybe scheduled construction on an exhibit makes the timing inopportune. Zoos or aquariums might make suggestions about which is least disruptive: moving a male or a female. Some species are patriarchal and some are matriarchal.


As an example of the latter, gorillas have an alpha male who is in charge, so we try to avoid moving a male into a troop where another male resides. You may recall that Ramar was already living independently before JoJo came to Brookfield Zoo. With primates, we also try to maintain family ties and are proud to house seven gorillas representing four generations at Brookfield Zoo. In contrast, dolphin social structure is matriarchal, so males are more likely to change institutions than females are. Bird species are more flexible and we can move either a male or female. However, we avoid separating pairs of birds like macaws, which form long-term bonds.

When we move animals as part of an SSP, we are improving the diversity of a threatened species’ gene pool so it may continue to survive, hopefully even thrive, on Earth.
Reintroduction to the Wild
For some animals, populations are dwindling in the wild but their habitat is not particularly threatened, so with careful monitoring and a thoughtful breeding program maintained among many organizations, new generations can be reintroduced to their natural habitats. For example, we are proud to have been selected to participate in the Gray Wolf Recovery Plan.

The care of animals in reintroduction programs is very different from others because they must learn survival skills. Animal care staff do not interact with the animals. They try to be as hands-off as possible. In fact, we want the animals to be leery of humans so they don’t run into trouble once they are reintroduced to native habitats.

As with the AZA SSPs, coordinating organizations—in the case of gray wolves it’s the U.S. Fish and Wildlife Service—direct which animals living in different institutions should breed, and with painstaking assessment and care, they also determine which animals should be released to the wild and when. Thanks to the success of this program, 97 Mexican gray wolves are back in their native habitat in the southwestern United States.


Puerto Rican crested toads are another example of an animal recovery and reintroduction program in which we participate with other organizations. The only toad native to Puerto Rico, this species is critically endangered in the wild. We keep a few of the amphibians on display so zoo guests can learn about their conservation story, but those bred for reintroduction are separated from the rest and carefully handled to prevent the transmission of disease from other toads. Since 1992, hundreds of thousands have been reintroduced in Puerto Rico from more than 20 participating zoos.
Animal Welfare
Sometimes it is in the best interest of a particular animal or its group to move an individual. In the wild, it is normal for the offspring of many species to leave or be pushed out from the group. It’s nature’s way of dispersing genes to avoid inbreeding and promote robust genetic diversity. For some animals, staying in a group can even be problematic for them. For example, at a certain age, male lions are pushed out of a pride.

When animals in managed care are no longer reproductive and space is limited, institutions may opt to transfer them where there is more room. To prevent problems in social structure, an institution may house only the males or females of a particular species, such as gorillas.

Again, in every instance, we ensure the safety and well-being of the animal, whether transferring from our facility to another zoo or vice versa. In instances when the partnering institution is not an AZA member, we are rigorous in our inspection of its facilities and staff to make sure they are as deeply committed to animal welfare as we are. If they don’t meet our high standards, we don’t send our animal.

New Animal or Habitat
In some cases, animals are transferred for a special engagement, such as the birds from last summer’s Festival of Flight or the Komodo dragon that will be part of our summer 2017 Dinos & Dragons exhibition. As with animals that are part of a Species Survival Plan, the utmost care is taken to ensure their safety, comfort, and well-being before, during, and after they are transferred.

At Brookfield Zoo, we know and appreciate that sometimes people grow fond of a particular animal and don’t want to see it leave. It’s hard for us, too! There’s a special emotional attachment that happens when you spend time getting to know a particular animal. And that’s our goal. We want people to feel connected to animals so that they will stand up for them and become wildlife advocates.
Conversely, it’s important that we keep animals’ preservation and well-being front of mind. That’s why we provide the safest, most uneventful and humane transfer of animals to ensure not only the welfare of that individual binturong, gorilla, or wolf cub but also the welfare of their entire species. 

This article originally appeared in Gateways, Brookfield Zoo’s member magazine.

Posted: 3/9/2017 12:36:29 PM by

Center for the Science of Animal Care and Welfare

Read the latest exciting stories about how our experts are advancing the science of “animal-directed” care through innovative programs at Brookfield Zoo and global field efforts.


Subscribe to our Blogs!RSS