Why did T rex have little arms?
In many creatures there exist vestigial structures, bits of the body that over time and many generations have become smaller as they’ve given no evolutionary advantage. Whales have little legs on a tiny pelvis hidden deep within their tubby bodies. Emus and other flightless birds retain small wings that are quite useless. Even in our own bodies there is a tiny tail at the bottom of our spine, not to mention Darwin’s tubercle; a muscle connector in our ears and countless other body parts that have drifted off into a miniature useless version of their former selves.
Not surprisingly it’s been hypothesized that T rex’s arms were tiny as they weren’t needed. Though if we look at the bones we can see that there are large areas for muscle attachments and indeed the bones were thick and strong. It’s been shown that T-rex’s tiny arms were likely somewhere in the order of three and a half times stronger than a human arm. Indeed you’d unlikely to win a T rex in an arm wrestle, mainly due to the fact that he would be chewing on your nubbly bits.
So what did he use his weeny arms for? Well it’s highly likely that they were some help at getting him upright again if he’d faceplanted. It’s also possible that they were used to hold struggling prey. One intriguing theory is that they were used to hold a mate, many creatures have evolved such ways of holding down some poor member of the opposite sex while they’re being humped… indeed it’s pretty understandable as to why there’d be a necessity to evolve something to stop their date leaving.
Why the most ghastly, grisliest, most dreadful blood-curdling creature ever to have walked the planet had silly little arms; we’ll probably never know. Though we rather like the idea of them being used to hold on to their partners in a passionate embrace; in other words his silly little arms might just have been used for cuddles.