Author Ted Crail learned his appreciation for animals at age 6, shortly after being told that a rare disease would kill him in a few weeks. He was given Christmas in September, and taken on a tour of Montana's magnificent wilderness and wildlife.

But it was the doctor who died, leaving Crail for the next few decades to enjoy a love for animals and a healthy skepticism for know-it-all experts. As he tells us, "I was left with a distrust of those who insist they know 'the scientific facts' and are very peremptory about it (I have been declared dying a time or two since)."

The result is this delightful book, which manages to be eloquent, moving and humorous while succeeding in substantively discussing a subject of immense scientific significance. As "Apetalk & Whalespeak" tells us, over the last two decades "increasing numbers of scientists, behaviorists, primatologists, and others have put their reputations on the line behind the claim that certain species can transcend the language barrier to express a rich and complex inner life of moods and feelings. Such claims strike at some of our most cherished ideas about the unique qualities that define a human and have thrown the scientific community into bitter debate . . ."

Crail covers the major animal-communication researchers, pioneers in a field as tantalizing as space travel, as well as introduces us to their subjects, some of whom have attained a celebrity status of sorts. Among these are the chimpanzees who have learned to "talk" through sign language, including Washoe, Lana and Nim Chimpsky.

He also discusses those courageous researchers and conservationists who have risked their lives and/or freedom to save imperiled wildlife. There is Dian Fossey, "fighting a losing battle . . . almost singlehandedly to save" the last 220 or so mountain gorillas left in the wild; Dexter Cate, who dove into a bay at night during a storm to cut a system of nets and free several hundred dolphins awaiting slaughter off Iki Island, Japan; and Steve Sipman and Kenny LeVasseur, who, while working on a dolphin communication project in Hawaii, "liberated" into the Pacific Ocean two of the cetaceans whom they felt were being mistreated.

Crail tells us of Jim Nollman, entrancing dolphins and whales with underwater music; of Dr. Roger Payne, who recorded and popularized the eerie and enchanting "song" of the humpback whale; of a humpback whale off Hawaii that stopped a tour boat to "ask for help" during an aborted birth; and many other enthralling and even astounding stories.

Experiments with certain species have led researchers to question whether such creatures as dolphins may in many ways be more intelligent than humans. Dolphin trainers trying to teach their performing subjects "tricks" commonly remark, with utter seriousness, "the dolphin trained me." Crail recounts many such anecdotes, such as a conversation with some Navy workers who had been involved in filming whales that had been taught to retrieve torpedoes and other objects. The Navy men told him that "not only were the whales marvelous at understanding the process the humans had taught them, but the whales soon felt they understood what was wanted better than clumsy sailors did. When the sailors fouled up, the whales would get sore and fuss--in gestures the humans could understand."

Crail's book is basically a happy, enjoyable one, but the awesome promise of what these surprisingly intelligent animals can teach us is haunted by the realization that we may end up destroying the subjects of our research before we are able to learn very much from them. The gentle, peaceful animals of Africa may not survive this century. Chimps are seriously threatened by poaching, loss of habitat, and capture for medical research (usually by shooting the mother and seizing the terrified infant).

Whales have bigger and more convoluted brains than do humans, especially the endangered sperm whale, which has the largest and most complex brain of any creature on earth. Yet, the Japanese kill almost 1,000 sperm whales each year for such products as chicken feed and tennis racket strings.

"Apetalk & Whalespeak" helps us to appreciate somewhat the nature and intelligence of these fascinating creatures with whom we share this planet, and to understand what a tragedy to humanity their loss would be. As Crail tells us on one of the few occasions wherein he reveals his inner feelings, "Our adventure into interspecies communication can turn out well only if we let it fan the greater movement for conservation of all that lives, walks, crawls and swims, and if we overcome our persistent human tendency to destroy all kinds of living beings except our own and to call our smashing of other worlds a 'civilizing influence.' "