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Scientists Take a Mighty Close Look at a Dinosaur's Butthole For the First Time Ever

Even though some birds, amphibians, reptiles, and some mammals have cloacae, we knew very little about dinosaur cloacae.

Scientists have a pretty good idea about what dinosaurs looked like, they can deduce things like if they were scaly, feathered, or horned for example. But what they haven't had a chance to discover and describe in much detail are these prehistoric creatures' backsides. Yes, we mean buttholes. 

But these aren't mere buttholes, these are cloacae, or vents, that have been pleasantly described as the "Swiss Army knife of buttholes," by Science Alert. Used for breeding, defecating, and urinating, these vents are found in vertebrates and are truly multi-purposed. 

Scientists from the University of Bristol managed to get a close look and describe for the first time ever what a Psittacosaurus dino's cloaca looked like, publishing their findings in Current Biology on Tuesday.

SEE ALSO: 7 ANIMALS TO IDENTIFY BY THEIR CHARACTERISTIC POOP

Thanks to these scientists, we now have a detailed description of a non-avian dinosaur's cloaca. Even though some animals today, such as birds, amphibians, reptiles, and some mammals have cloacae, very little was yet known about dinosaur cloacae — up until now. 

"I noticed the cloaca several years ago after we had reconstructed the color patterns of this dinosaur using a remarkable fossil on display at the Senckenberg Museum in Germany which clearly preserves its skin and color patterns," explained palaeobiologist Jakob Vinther of the University of Bristol.

Scientists Take a Mighty Close Look at a Dinosaur's Butthole For the First Time Ever
A close up of the dinosaur's preserved cloacal vent. Source: Study authors/University of Bristol

So Vinther and his team decided to compare the fossilized cloaca to modern-day ones. The team could only gather information about the exterior of the fossilized cloaca, as the interior was not properly preserved. 

Dr. Diane Kelly, an expert on vertebrate penises and copulatory systems from the University of Massachusetts Amherst, also working on the study said, "Indeed, they are pretty non-descript. We found the vent does look different in many different groups of tetrapods, but in most cases, it doesn’t tell you much about an animal’s sex."

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Scientists Take a Mighty Close Look at a Dinosaur's Butthole For the First Time Ever
Cloacae of different animals. Source: Jakob Vinther/Current Biology

Regardless, the exterior of the cloaca could provide decent information about what the dinosaur's "vent" looked like, and how it was used. The team found out the dino cloaca was different from those of living creatures, however, it shares similarities with those of crocodilian reptiles, like alligators and crocodiles. 

Scientists Take a Mighty Close Look at a Dinosaur's Butthole For the First Time Ever
The fossilized specimen from the Senckenberg Museum of Natural History. Source: Jakob Vinthers/University of Bristol

One interesting facet the researchers noticed was the dino's cloaca's outer margins were highly pigmented with melanin, which means it may have been used as a signaling system, similar to baboons today. 

As Robert Nicholls, a colleague working on the study and a paleoartist, said "Knowing that at least some dinosaurs were signaling to each other gives palaeoartists exciting freedom to speculate on a whole variety of now plausible interactions during dinosaur courtship. It is a game-changer!"

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