The DNA of chimpanzees is 98.4% identical to that of humans, according to evidence law scholar and author David McCord, the Richard M. & Anita Calkins Distinguished Professor of law at Drake University Law School in Des Moines, Iowa. In the following short article, Professor McCord takes the logical (?) next step and ask whether we should, therefore, permit chimpanzees or other great apes to testify as witnesses. The article first appeared in the Evidence Newsletter of the Association of American Law Schools, in the Fall of 1999, and is reprinted here with the permission of the author.

Can Apes Testify?

Comment by David McCord

Human DNA and chimp DNA are 98.4% identical. Humans are genetically closer to chimps than chimps are to bonobos (a second, smaller species of chimp). All four species of "great apes" -- chimps, bonobos, gorillas, and orangutans -- have an identity of at least 96.4% with human DNA. Is it any wonder, then, that scientists have discovered that great apes have substantial language abilities? And, from a legal standpoint, if language abilities, then why not competence to testify?

The popular press reported in late summer that a group of animal rights activists is planning to follow this line of reasoning by crafting a case where an ape will be offered as the star witness. The Great Ape Project, a part of the Animal Legal Defense Fund, hopes to present an ape to testify, via sign language or a voice synthesizer, in support of a claim that apes have fundamental legal rights, including the right to liberty.

How should evidence law approach this novel admissibility issue? A straightforward approach would be to hold that only humans can be witnesses. This is certainly true as a historical matter, but it eliminates some really interesting evidence questions -- as well as being a product of the very "our-species-is-unique-and-superior" presupposition that the Great Ape Project is trying to challenge.

A second, more interesting approach would be to treat an ape just like a human witness, and focus on the four testimonial capacities: perception, memory, sincerity, and communication. If the ape has each capacity in sufficient degree, the ape should be competent to testify. For run-of-the-mill apes, it is easy to conclude that they lack at least the ability to communicate. Such apes, while "smarter" than dogs, possess no mechanism to communicate with humans to a much greater extent than dogs do.

But there are a minuscule number of apes that have been trained by humans to communicate in human languages -- through American Sign Language, or via pictorial computer symbols. Some scientists doubt that such apes are really thinking and speaking on their own, but reading the book Next of Kin (written by chimp language researcher Roger Fouts) should convince any fair-minded observer that specially-trained chimps do indeed gain more than minimal competence in a humanly-understandable language. They can correctly perceive objects and events, can remember them (Fouts tells the story of an ape he hadn't seen for years who immediately recognized Fouts and called him by his nickname), and can communicate their observations and desires to humans.

There remain, though, at least two major competency problems. The first relates to sincerity: it is well documented that language-enhanced apes sometimes lie when it is in their interest to do so -- although the lies are usually transparently obvious. It is difficult to see how the responsibility to tell the truth in a court proceeding could be impressed upon an ape. The second problem relates to the apes= still limited ability to communicate: a witness has to be competent not only for direct exam, but also for cross. It is hard to see how an opponent could meaningfully cross-examine an ape. (Of course, once one starts dealing with testimonial capacities, inevitably hearsay questions arise. Are there any greater or lesser risks associated with out-of-court statements of language-enhanced apes than with out-of-court human declarants?

A third possible approach might be to treat language-enhanced apes as a sui generis category of demonstrative evidence, and to apply some less strict analogs of the four testimonial capacities to them.

However this all shakes out, it promises to be one of the most intriguing evidence issues in recent memory.