An Italian biologist has shown humankind is not the only species to indulge in vices like lust, avarice and gluttony.
University of Bologna professor Giorgio Celli exposes the animals that are guilty of the seven deadly sins in his latest book - 'I Sette Peccati Capitali degli Animali' (Animals' Seven Capital Vices).
Readers learn, for example, that lust is the favourite form of misbehaviour of the bonobo chimpanzee of central Africa.
The bonobo often copulates many times a day, practises a wide variety of sexual positions and enjoys oral sex and homosexual relations too.
"The complexity of their erotic games is amazing and it goes well beyond their reproductive needs," Celli explained at the book's presentation.
Lots of animals are guilty of gluttony, he said, but some herds of African elephants combine this sin with drunkenness.
The elephants get tipsy by gorging on the sugar-rich, fermented fruit rotting on the ground at the bottom of marula trees.
"The elephants don't consume this fruit because they need to, but because they find it pleasurable," said Celli.
The red squirrel is guilty of avarice, he noted, hoarding more seeds and nuts for the winter than it will ever be able to eat.
Dogs are particularly prone to envy when their masters divert their attention to other pets, Celli said.
"Take the case of two dogs who lived together in the same house," he explained.
"One of them got sick, so his owners put him in a separate room, which the other was not allowed into.
"The second one got so jealous that he attacked the ill dog during the night."
The domestic cat is among the slothful species, sleeping away 18 hours of the day, said Celli, who gives numerous examples of many wild animals' pride and wrath too.
As well as highlighting some fascinating aspects of animal behaviour, the book also challenges the conventional wisdom that says a sense of right and wrong is the preserve of humankind.
"Maybe it is not true that animals just exist and that they are not capable of being good or bad," he said.
"The aim of this book is to trace the biological origins of morality".
Celli's believes that when humans domesticate animals we bring them into our "ethical universe".
But this is only possible, he argues, because there is an dormant sense of morality in the "heart of the animal" that humans manage to develop.
"When dogs do something wrong they try to hide the evidence or hang their ears in shame when they are found out," he said.
"This is because the animal has sensed a moral rule and feels it has done wrong".
Furthermore, Celli claims that 'animal morality' is not always inferior to its human version.
"A male wolf will fight hard to have leadership of the pack, but he never kills his rivals," Celli said. "Humans should do they same".
