When you find yourself rubbing the genitals of a wombat, you might start to rethink your life choices. Perhaps you imagined sitting on a tree branch staring at a troop of chimpanzees through your binoculars, tracking the movements of polar bears from a small floatplane, or counting fish on a tropical reef. Some researchers do those things, but wildlife science isn't usually so glamorous. Sometimes you spend your days coaxing a wombat to pee.

In 1927, Russian physiologist Ivan Pavlov discovered the rules underlying one of the most basic forms of learning in humans and animals. In 2014, those rules are being implemented by researchers working on wombat conservation.

“You've heard of Pavlov's dog? Now meet Pavlov's wombat.”

Pavlov knew that putting some meat powder in front of a dog would cause it to salivate. It was an automatic, reflexive response. When the dog smells the meat, its body's physiology begins preparing for a feast. Pavlov realised that if the sound of a bell was always followed by the smell of meat, then eventually the dog would start salivating at the bell's tone alone. 

The dog eventually learns an association between the bell and the meat, resulting in an involuntary, automatic, reflexive response to something – the bell – that was previously neutral. That form of training is called classical conditioning. Now, every high school and college student enrolled in an introductory psychology course learns about it.

You've heard of Pavlov's dog? Meet Pavlov's wombat.

Unlike a human child visiting a doctor, a wombat won't just urinate on command. Wombat urine could be collected from the floor of their enclosures, but then all sorts of other microbes would contaminate it, and it could also be difficult to know which urine came from which wombat. 

Common Wombat 2014 09 18
Two of the three wombat species are classified as threatened by the IUCN. The common wombat (pictured) is listed as 'Vulnerable' and the northern hairy-nosed wombat as 'Critically Endangered'. Image: Nuytsia@Tas, Flickr

It might be a giggle-inducing topic, but the ability to reliably collect urine samples from wombats is actually an important advance in their conservation. Since two of the three wombat species are classified by the IUCN as threatened (the common wombat is 'Vulnerable' and the northern hairy-nosed wombat is 'Critically Endangered'), researchers and conservationists have implemented captive-breeding programmes.

For the best chances at successful breeding, caretakers need to know when the wombats will be most likely to mate and conceive. The problem is that the relationship between the reproductive physiology of wombats and their breeding cycle is still quite poorly understood. Taking blood samples requires that the animals be captured, restrained and sedated. The process can be stressful to wombats and dangerous for humans. And researchers can't reliably detect oestrogen in faecal samples. Urine, on the other hand, has everything that scientists need, and can be collected relatively easily.

So researcher Alyce M. Swinbourne of the University of Queensland's Wildlife Science Unit had a brilliant idea. "I wanted to know if females which entered captivity as wild-caught juveniles could be trained to urinate," she said. 

Swinbourne and her colleagues chose four captive female southern hairy-nosed wombats (Lasiorhinus latifrons) as experiment participants. Two of the animals were hand-raised, and two were wild-caught. (A fifth wombat was excluded from the study because she was too aggressive.) Reared wombats are used to interacting with humans and therefore naturally easier to train – would Swinbourne's experiment work for wild wombats as well?

Twice a day for 35 days – once in the morning and once in the afternoon – the researchers manually stimulated the wombats' genital regions (like some birds, female marsupials have a cloaca rather than a vagina). They continued the rubbing until the wombat began to pee, even if it took up to 25 minutes.

Wombat Urine Pavlov 2014 09 18
The researchers manually stimulated the wombats' genital regions - twice a day for 35 days, sometimes for up to 25 minutes at a time. Image: Swinbourne et al. 2014

Each wombat had a spot where she preferred to urinate, a de facto latrine (a corner of her enclosure, perhaps, or inside the next enclosure over) – so the wombats already had an association between their makeshift toilets and the act of peeing. Using classical conditioning, the researchers hoped to create an association between cloacal stimulation and urination. Pavlov used meat powder and a bell; Swinbourne used a latrine and genital massage.

By the end, Swinbourne had successfully trained each of the four wombats to urinate on command. By the time the experiment was over, Swinbourne could reliably retrieve a urine sample 82% of the time, after just two to four minutes, on average, of cloaca rubbing.

"For keepers and investigators," she wrote in her report, which was published earlier this month in the journal Zoo Biology, "classical conditioning can be a powerful tool for decreasing stress associated with husbandry procedures."

By taking one of the most fundamental aspects of animal learning and applying it in the complex business of animal husbandry and management, Swinbourne may have brought us one step closer to being able to protect these unique animals. She can now use this technique to understand more about the daily fluctuations in wombats' urinary hormones.

Because the animals were able to associate the rubbing of their cloaca with the desired behaviour (urination), she thinks that other cues could be used as well, like the sorts of whistles or clickers used to train pet dogs. That would probably be a relief to the researchers who had to spend up to 25 minutes rubbing the wombats' genitals, twice each day. It's not quite as romantic a prospect as it sounds.

Top header image: Daniela Parra, Flickr