Date Night for Tyrannosaurus Rex: A Theory

Tyrannosaurus Rex is generally viewed as the most feared of all the dinosaurs (save for my personal hangup regarding Plesiosaurs, but that’s another issue brought on by an irrational fear of the Lock Ness Monster). Paleontologists’ perception of the Tyrannosaurus has undergone a variety of changes over the past two decades, with the dinosaur going from a fast-moving predator to a lumbering scavenger and back again.

One of the most interesting areas of  T. rex and dinosaur research in general, however, involves something near and dear to us humans: sex. How did the king (and queen) of the lizards make love and create precious little baby dinosaurs? Let’s find out.

A Lack of Fleshy Data

There is a general lack of information about the fleshy protuberances and genitalia (i.e. the penis and vagina) of Tyrannosaurus rex, as examples of impressions of soft tissue in the fossil record is extremely rare. It is generally assumed that the terrible lizard mated in the most common fashion in the Animal Kingdom—from behind, in a “doggy-style” position.

It is theorized that most dinosaurs, due  to their size, used a version of this position to copulate, possibly wrapping tails as well to maintain balance. Paleontologists also suggest that having sex in a shallow body of water would help offset the weight and balance issues. Female Tyrannosaurs were also a good bit larger than adult males, further complicating the matter.

Stubby Arms: The Better to Hold You With

The short, stubby arms of Tyrannosaurus Rex likely played a role in delivering food to the dinosaur’s mouth, as well as providing for additional traction during intercourse. A male T. rex probably used these forelimbs to hold on to the back of a female T. rex, using the primordial hands to grasp onto patches of scales or feathers. Paleontologists also suggest males might have bitten down on the neck and back of the female in order to maintain grip and traction during copulation.

The Jurassic Museum of Asturias in Spain currently has an entire exhibit dedicated to Tyrannosaurus rex, including life-size skeleton casts fixed in mating position.


Where Did T. Rex Hide His Man Parts?

Tyrannosaurus rex towered above the predators of its era at an adult height of 20 feet and weighing in at around seven tons, making one wonder what size its sex organs would be and why they are curiously deleted from depiction of the dinosaur in cartoons and movies. The answer is pretty simple: T. Rex probably kept his male unit (estimated at 10-12 feet) hidden away in a body pouch called a cloaca, a pouch used by other reptiles including crocodiles.

There is also the possibility that Tyrannosaurus rex lacked a male sex organ that we would recognize as a penis. Cloacal “kisses” are a common form of reproduction in the birds, relatives of these humongous lizards. Cloacae are openings used for defecation, urination, and sex, with these openings seen in amphibians, fish, and birds. In a cloacal kiss, a rush of blood could swell the male cloaca, with semen excreted along the bulge and transported when the male cloaca came in contact with the female’s cloaca.

While the methods by which T. rex reproduce are under some debate, we will never really have a definite answer unless dinosaur cloning ala Jurassic Park becomes a reality or some lucky paleontologists get to visit the Jurassic Period via time machine. In the meantime, dinosaur sex will remain an interesting area of research, one that easily piques the public interest.

Image Source: Abin Olsson/Wikimedia Commons

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