[1][2] All cats descend from the Felidae family, sharing similar musculature, cardiovascular systems, skeletal frames, and behaviour.

[12] In the larynx, there are vocal folds that produce the structure needed to stretch the ligament to a length that creates the roar effect.

[13] When this large pad folds it creates a low natural frequency, causing the cartilage walls of the larynx to vibrate.

[14] All five extant members of the genus Panthera contain this elongated hyoid but owing to differences in the larynx the snow leopard cannot roar.

To be accepted by the United States Fish and Wildlife Service (FWS) as a bona fide animal sanctuary and to be eligible for an exemption from the prohibition of interstate movement of big cats under the Captive Wildlife Safety Act (CWSA), organizations must meet the following criteria:[25] Internationally, a variety of regulations are placed on big cat possession.

The principal threats to big cats vary by geographic location but primarily consist of habitat destruction and poaching.

[36] To address problems associated with the increasing trade in certain big cat species, the CWSA regulations were strengthened by a law passed on September 17, 2007.

Private ownership is not prohibited, but the law makes it illegal to transport, sell, or purchase such animals in interstate or foreign commerce.

Although these regulations seem to provide a strong legal framework for controlling the commerce involving big cats, international organizations such as the World Wildlife Fund (WWF) have encouraged the U.S. to further strengthen these laws.

The WWF is concerned that weaknesses in the existing U.S. regulations could be unintentionally helping to fuel the black market for tiger parts.