Nature & Environment » Animals

The best books on Dogs

recommended by José Castelló

Interview by Sophie Roell

Next time you look at your cute pooch, remember its DNA is the same as that of a wolf. José Castelló, author of the delightful field guide, Canids of the World: Wolves, Wild Dogs, Foxes, Jackals, Coyotes, and Their Relatives recommends some of the best books to read on dogs and other canids.

Can I start by asking a question which I hope doesn’t sound silly: what is a dog?

That is, in fact, a very interesting question. Currently, most authors consider the domestic dog, despite the huge variety in size and shape of the multitude of dog breeds, to be just a domestic variant of the grey wolf. Therefore, from a taxonomic point of view, it’s classified as a subspecies of wolf: Canis lupus familiaris.

In the 1990s, multiple DNA studies were conducted to clarify the origin of the domestic dog, concluding that wolves and dogs have a common extinct ancestor, and therefore belong to the same species. In 1993 the scientific name of Canis familiaris was changed to Canis lupus familiaris. Dogs and wolves are so closely related that DNA analysis cannot distinguish a wolf from a dog or a wolf-dog hybrid. Coyotes or jackals, however, can be distinguished from wolves or dogs through DNA analysis.

“Whereas the wolf is a generalist, the dog has been selectively bred by man over some 15,000 years to specialize in traits important to humans”

Dogs are also the oldest domestic animal in the world. The first vestiges of this process are in fossils around 32,000 years old, and domestication probably occurred in Europe or in Asia. However, it is not entirely clear if man domesticated the dog or they domesticated themselves, as a way of survival.

Dogs retain many characteristics of their wolf ancestors, but whereas the wolf is a generalist, the dog has been selectively bred by man over some 15,000 years to specialize in traits important to humans. If we compare a dog with its ancestor, the grey wolf, a dog has a smaller skull and brain, its dentition is also reduced, as well as its need for caloric intake. All this was caused by domestication, since they didn’t need to go hunting.

For dogs, humans form their social group. In contrast, wolf packs virtually never go around accepting strangers into their social groups. A wolf pup would not turn out like a dog if raised with humans. Wolves are definitely not dogs; they do not behave like dogs and cannot be domesticated. In the wild, dogs may occasionally be accepted into wolf packs. However, the typical result is that the dog is driven off or killed.

If they are all the same subspecies, how come domestic dogs look so different from each other, then?

After the domestication of the dog, our prehistoric ancestors favoured different abilities in their dogs (e.g. hunting in burrows, or herding), which resulted in the creation of different breeds, each with distinctive characteristics. These changes were slight at first, but after many generations of breeding animals with similar characteristics in a process known as artificial selection (as opposed to natural selection), these changes gradually increased. Thus, we ended up today with a huge diversity of dogs that look very different.

“Dogs and wolves are so closely related that DNA analysis cannot distinguish a wolf from a dog or a wolf-dog hybrid”

This process is completely controlled by man. However, from a genetic point of view, all breeds are virtually identical. In fact, dogs from different breeds, allowed to breed freely in the wild, will acquire a more ancestral appearance after a few generations. One of the downsides of this artificial selection of breeds is the involuntary selection of certain kinds of diseases, like hip dysplasia in German Shepherds, or breathing problems due to skull defects in Pugs.

Your first choice is Jack London. I think we can talk about both Call of the Wild and White Fang as they’re available in a single volume. Why do you recommend these books? 

Well, both are timeless classics that are easy to read over and over. I read both when I was a kid, one after the other. Those were my first books about wild animals and nature, and I probably started loving the beauty of the wolf at this time. London’s prose is passionate and evocative; it transports the reader to the brutal, beautiful wilds of Yukon and the lives and minds of the wolves, dogs, and men.

Do the books present an accurate picture of how dogs and wolves think and behave? 

We should give London some literary licence. For their time, these books don’t seem to be too bad. Back then—White Fang was published in 1906—the knowledge of wolf behaviour was limited. People still had a widespread fear of wolves during London’s time. The savage wolf pack stalking the two woodsmen in White Fang was just a hook to terrify and lure in readers. It’s high adventure, and should be taken as such.

In Call of the Wild, Buck is presented very much as the alpha male. Do canids always have a pack leader in this way?

Wolves exhibit a flexible social system, from living in families (a monogamous breeding pair and their offspring) to more complex social groups with unrelated members. In family packs, there is an age-graded dominance order in which offspring submit to parents and puppies submit to older siblings. Members of the dominant breeding pair usually lead pack movements, and often only the dominant pair breeds.

“Domestic dogs rarely form packs with hierarchical structures”

In contrast, domestic dogs rarely form packs with hierarchical structures. Free-ranging wild dogs are usually semi-solitary animals or live in social groups of mainly unrelated members that do not have a hierarchical social structure affecting group activities. A dog that goes feral or wild, like Buck, will rarely or never join an existing wolf pack. Such a dog may eventually mate with a wolf that has left its original pack and is looking for a mate. But most wolf packs will consider a dog an intruder, and will kill him.

Tell me about The Killing of Wolf No. 10.

This is the story of the first wolves reintroduced to the area of Yellowstone, and it demonstrates how many factors, from political to emotional, came together. The Killing of Wolf No. 10 is a very sad but wonderful tale of a wolf who lived a short but spectacular life; it perfectly depicts the typical confrontation between wolves and communities, seen across many parts of the world.

Do you think reintroducing wolves is a good idea?

This is probably one of the most controversial topics among the scientific community. There is no single answer to the question. It also depends on the geographical area we are talking about. In many cases, the wolf, if left alone, is able to expand and repopulate large areas without the need for specific reintroductions, as is happening now in Spain. In other areas, like Japan, reintroductions would be the only way to bring back wolves from extinction. (Wolves used to live in Japan until 1905.) This is seen as a way to (re)introduce an apex predator to the ecosystem, which is essential for sustainability and avoids the overpopulation of ungulates. Yellowstone’s reintroduction is always cited as an example of this. However, most of these repopulations or reintroductions face opposition from ranchers and hunters, and in most cases, there is a strong political pressure not to pursue it.

Your next choice is The Secret World of Red Wolves: tell me what this book is about and why you’ve recommended it.

The history of this species, the red wolf (Canis rufus), is a very interesting example of the importance and relationship between taxonomy and politics in the conservation of some species. The red wolf is considered as a species of wolf, native to the southeastern US, closely related to the grey wolf, but distinct, and listed as ‘critically endangered.’ However, some authors have recently suggested that it may be nothing more than a hybrid between coyotes and grey wolves. If so, it will lose its conservation status and protection, given that US legislation does not protect hybrids, leading to the extinction of this animal.

“This book is really a must-read for anyone interested in North American ecology”

This book explains this and much more. It is easily the most complete book written on these wolves. It summarizes the red wolf from its origins to current research, explores efforts to re-establish it, and current and future threats to the species. The book is divided into three main parts: ‘The Red Wolf Today,’ ‘The Red Wolf Yesterday’ and ‘The Red Wolf Tomorrow.’

Get the weekly Five Books newsletter

In the first section, written as a first person narrative, Beeland describes the efforts to re-establish a population of wild wolves in northeastern North Carolina. We meet the biologists and some of the red wolves themselves. This book is really a must-read for anyone interested in North American ecology, and readers will have a much better appreciation for this species. The book is both scientifically compelling and accessible to all. Hopefully, new conservationists will champion the recovery of red wolves after reading this book. As the author says, the story of the red wolf was waiting to be told, and it is a very interesting and tragic story at that.

How many red wolves are there now? 

The red wolf was once found throughout forested regions of the American southeast. As a result of aggressive predator control programs and the loss of forest habitat, by 1970 its population had declined to less than 100 wolves and was confined to a small area of coastal Texas and Louisiana. Early recovery attempts were largely unsuccessful and the remaining wolves began mating with coyotes. As a result, the number of pure red wolves decreased and further contributed to the species decline.

In 1973, in a final attempt to save the species, efforts were initiated to capture as many wild red wolves as possible. 17 pure red wolves were captured by biologists and became the founders of a captive breeding program. In 1980, the last remaining wild red wolves were brought into captivity and the species was declared extinct in the wild. By 1987, enough red wolves were bred in captivity to begin a restoration program in North Carolina.

Since then, the experimental population area has slowly expanded to include three national wildlife refuges. In 2003, approximately 100 red wolves existed in the wild, but the wild population is once again dwindling to a mere 30 or 40, amongst political controversy and pressure from a number of landowners to be allowed to shoot the wolves on their land.

Thank you for supporting Five Books!

Although the red wolf recovery program once served as a model for the successful recovery of wolves, political barriers seriously threatened the continued existence of this endangered species. In 2014, the US Fish and Wildlife Service (USFWS) stopped reintroducing red wolves into the wild and began issuing kill permits to landowners. In a recent proposal announced in 2016, the agency called for placing most of the last remaining wild red wolves in captivity. In 2018, USFWS confirmed what has been evident: the wild population is in crisis and could go extinct within eight years. Termination of the recovery program will inevitably result in the loss of the last population of red wolves, rendering the species ‘extinct in the wild’ in the next few years.

Next up is The Biology and Conservation of Wild Canids. Tell me about this book and why you like it.

This book is definitely not for the general reader, but it is probably the most complete text on the biology and conservation of wilds canids, synthesizing all the research done in the last twenty years in this field. Edited by two of the world leading experts in conservation and research on canids, David Macdonald and Claudio Sillero-Zubiri (who also wrote the foreword to my book, Canids of the World), the book cleverly gathers together expertise from around the world to create a text that specifically addresses current research about canids.

It includes a complete account of all 36 species, with an emphasis on topics most relevant to conservation science, including evolution, systematics, ecology, genetics, diseases, conflict and control of troublesome species, and conservation. It also focuses on protection of the most threatened species, such as the Ethiopian wolf or the African wild dog. Even though it’s already 14 years old, this text is of fundamental and lasting value to all canid researchers and graduate students, and to those interested in the ecology and conservation of wild canids and the management of wildlife.

Is there an interesting fact in the book about canids that maybe most people don’t know? 

The book is full of interesting facts. For example, many social canids exhibit behaviors which are unusual among most mammals, such as reproductive suppression or alloparental care. Only a dominant male and female in the group can reproduce. Subordinate members are not allowed to breed (they are socially repressed, or the dominant pair may kill their pups), but they will babysit and care for the pups of the dominant pair, and will provide them with food. In some species, such as the Arctic Fox or the Wild Dog, non-breeding females will even breastfeed the offspring of the alpha pair.

How do dogs and canids compare in intelligence to other animals such as pigs, cats and so on?

It is not easy to measure the intelligence of animals, but what is certain is that canids are one of the groups with the greatest ability for adaptation, and therefore intelligence. Until recently, the wolf was the terrestrial mammal with the widest global distribution, thanks to its ability to adapt to climate changes, and to different habitats: from deserts to Arctic zones, from remote areas to those in proximity with human populations. Currently, that place is occupied by the red fox, which is another species of canid, which also has an immense capacity for adaptation. From a social point of view, unlike most felines, canids form stable breeding pairs in which the male helps the female rearing the young, allowing litters of more individuals than in other groups of mammals. Large canids also form social groups, which allows them to hunt larger prey and defend themselves against other predators. These groups have complex hierarchies, with only one breeding pair, and possess very rich communication systems.

Dogs also have about twice the number of neurons in their cerebral cortexes as cats, and according to some scientists, dogs’ mental abilities are close to a human child of age 2 to 2.5 years. As for language, a dog can learn 165 words, including signals, can count up to four or five, and also have a basic understanding of arithmetic. Based on the relative size of the brain (compared to the animal’s body size), the most intelligent animals are humans, followed by great apes, porpoises, and elephants. The dog is close behind elephants. Descending down the list we find cats lower than dogs, followed by horses, sheep, mice, rats, and rabbits. As a general rule, animals that hunt for a living seem to be brighter than strict vegetarians.

Thank you for supporting Five Books!

Dogs have been bred to thrive in a human-generated environment, so they’re particularly adept at reading human social cues. Animals that live in social groups are generally smarter than solitary animals, as they must engage in problem-solving every time they interact with another animal in the group. This is also consistent with the fact that dogs may be more intelligent than cats, since dogs are much more social animals, and interaction in packs often involves complex behaviors.

Lastly we we have Dogs: Their Fossils Records and Evolutionary History. Tell me about this book. 

This book, written for both specialists and general readers, provides an engaging account of the ancient origins of the dog family. The authors devote different chapters to systematics, taxonomy, diversity, behavior, ecology, biogeography, morphology, and the impact of environmental change, providing a complete picture of the evolution of this family. One chapter is also devoted to surveying major issues in the study of domestication.

One element that makes this book exceptional is the art. The exquisite scientific illustrations by Spanish artist Mauricio Antón of the fossils, as well as reconstructions of what the animals would have looked like, make the text so much more enjoyable. Anyone interested in canids, fossils, evolution, the origin of the dog, and domestication should find this volume appealing.

Why are there no big predator dogs (like there are cats)? 

The canids which do attack large herbivores (such as wolves, dholes and wild dogs) generally do so as a group, while most cats will hunt solitarily. As a result, selection for an increased body size for the exploitation of large prey has occurred less in canids than it has in felids. Felids generally stalk prey or lie in ambush and then make a short dash to strike down prey; this specialized method of hunting has resulted in significant anatomical adaptations (e.g. size, claws, short face), while canids are adapted for cooperative longer chases, in which body size, speed and strength are less important.

I was very interested in the book to read about the origin of dingoes (our own dog looks almost exactly like a dingo, though we adopted her from a shelter in New York State so I think it’s not possible). So dingoes used to be domesticated? 

Although there is some debate regarding the taxonomy of Australian dingoes, they are currently regarded by most authors as feral dogs, descended from domesticated ancestors brought from Asia to Australia by men. Dingoes and dogs are the same species, and both are considered as subspecies of wolves. Most of the dingoes that inhabit Australia are not pure anymore, as they are the result of crossbreeding with European domestic dogs brought to Australia during European colonization. The appearance of dingoes may in any case resemble those of our ancestral domestic dogs.

There are no dingoes in the United States—apart from those in zoological collections—but there are several primitive breeds of dogs, such as the Carolina dog, also known as the ‘American Dingo.’ They look like, and behave similarly to, ancestral dogs. Interestingly, the Carolina dog breed miraculously remained undiscovered in the American South until the 20th century and has a certain resemblance to Australian dingoes. So, it’s possible your dog belongs to that breed . . .

Interview by Sophie Roell

March 13, 2019

Five Books aims to keep its book recommendations and interviews up to date. If you are the interviewee and would like to update your choice of books (or even just what you say about them) please email us at

José Castelló

José R. Castelló is a medical doctor, naturalist, and wildlife photographer. He is a member of the American Society of Mammalogists and the Spanish Society for Conservation and Study of Mammals.