The world’s most romantic animals

ANIMALS have very similar relationships to humans. From stage five clingers, to dudes under their girlfriends’ thumb. Find out which critter is you.

An Aotus lemurinus, known as an owl monkey, carries its one-month-old baby on its back after it was born in captivity at the zoo in Medellin, Colombia, Tuesday, May 19, 2009. (AP Photo/Luis Benavides)

IF YOU thought it was hard to find a reliable partner then spare a thought for most of the creatures in the animal world where monogamy is extremely rare.

But there are a few species that buck the trend and could even have a few lessons to teach us humans.

Most recently, scientists were excited by research that identified the first primate shown to be faithful partners — Azara’s owl monkeys.

Researchers were able to confirm through testing that the children of 17 pairs of owl monkeys that were a genetic match, proving that the species don’t cheat.

So far genetic monogamy has only been identified in four mammals. These are the California mouse, Kirk’s dik-dik, the Malagasy giant jumping rat, and the coyote.

“It used to be thought that many species — especially birds — were strictly monogamous, but as a result of DNA fingerprinting combined with intensive field observations, we now know that there is a huge difference between “social monogamy” (essentially, shared housekeeping) and sexual monogamy (sex only with one partner),” Professor David P Barash told news.com.au.

Loyal partners: A coyote on the prowl in Yosemite National Park.

The Professor of Psychology at the University of Washington has written a book The Myth of Monogamy, and said even social monogamy was very rare among mammals.

There are some exceptions, such as beavers, gibbons, some foxes and the Malagasay giant jumping rat.

Prof Barash said that even among most supposedly monogamous species, females in particular were very good at hiding their liaisons, so when biologists observed them, they were typically fooled into thinking they are faithful ... just as the female’s mate is.

“In such cases, it’s only when we do extensive DNA fingerprinting that we discover that even those animals that appear to be very faithful aren’t necessarily so,” Prof Barash said.

Is this the clingiest partner in the world?

Prof Barash said his favourite example of a guaranteed lifetime monogamous animal was the Diplozoon paradoxum, a flatworm parasite commonly found on the gills of European cyprinid fishes.

The flatworm begins life as an egg laid in the fish gills. It hatches and continues to grow for several months but in order to live it needs to find a mate and “fuse” together with them.

“In this species the male and female encounter each other as adolescents after which their bodies literally fuse together ... so they remain monogamous until death do they not part,” Prof Barash said.

Two flatworms fused together, until death they do not part.

Hands on fathers could be more faithful

When researchers studied the Owl Monkey, which is the first primate identified as genetically monogamous, it also found that the males were fully committed to caring for their children.

“There is nothing like this in other primates or mammals,” Lead author of the study Eduardo Fernandez-Duque told NBC.

“Every single male studied over 18 years in captivity and in the field has shown devoted care.” When you see a baby riding on an adult, “you can put your money down — the adult is a male.”

Fernandez-Duque and his colleagues collected data on 15 species of mammals that were thought to be monogamous. They found that the less promiscuous the species were, the more time they spent with their children. The study could not determine which came first.

Doting parents: Owl monkey fathers look after their children. AP Photo/Luis Benavides

“The findings suggest that pair-living mammals are more likely to commit to the evolutionary leap of genetic monogamy if pairs spend very little time independent of one another and if males offer intense care,” the authors write.

Two other studies published last year had conflicting explanations of how monogamy originated. One argues that males stayed with their mates to protect their children, while the other suggested they wanted to protect their breeding rights with a certain female.

Anthropologist Kermyt G Anderson of the University of Oklahoma, said the link between monogamy and fathers caring for their children seemed to fit evolutionary theory.

“Males should invest in their offspring only if it’s likely to be their offspring,” he told NBC.

Or your partner could be a bit macho

Kirk’s Dik Dik is one of the four mammals found to be genetically monogamous and scientists have suggested that is this because the males guard their mates very closely.

This may also limit the males’ ability to search for some hanky-panky on the side, because they are thought to spend about 64 per cent of their time with their partners.

However, when the opportunity does arise, the male dik dik is likely to pursue liaisons with a different female so scientists believe that the reason why they are genetically monogamous is because females do not look for other mates, possibly because it is potentially dangerous.

“We propose that females avoid extra-pair males because they are unable to mate with them without instigating a potentially dangerous conflict,” a study into their behaviour states.

Too scared to cheat: Kirk's Dik-Dik fear the consequences of cheating.

The biggest cuckolds

It used to be thought that many birds were sexually monogamous but genetic tests have found that about 90 per cent of bird species are not.

“Among birds, we now know that its not uncommon for 15, 25, 35, even 50 per cent of chicks to be fathered by a male other than the female’s social partner,” Prof Barash said.

Even among birds that are socially monogamous, over 11 per cent of their chicks were on average not genetically matched to their father.

The famous cuckoo, which lays its eggs in other bird’s nests and after which the term cuckold is named. AP Photo/Mark Hamblin, RSPB/PA