Dinosaur tail whip makes no sense.

There's a recent paper published dispelling a long-held belief (myth?) that Diplodocid sauropods such as Apatosaurus and Diplodocus used their long whip-like tails as whips! Okay, this doesn't sound that outlandish, what always got me questioning this even as a child is the part where the tails act like whips creating cracking sounds (mini sonic booms) to scare away predators. This always sounded insane to me. The newly published paper agrees with me, but their reasoning is different from mine. I'll explain my thoughts at the end.

The new research was done with computer simulation rebuilding the tail and just whipping it to see whether it can be done. They found that the tail could only move at the speed of 33 meters per second whereas you need to move at the speed of 340 meters per second to achieve the speed needed to create these mini sonic booms. If the sim moved at the speed of 340 meters per second, the tail can't withstand that level of stress and would just break. This makes perfect sense! This is something I hadn't even considered, but it makes perfect sense.

The thing that got me questioning this as a child is simpler. In order for a tail crack to happen, the whip has to hit something for that sound to be generated. I couldn't for the life of me imagine how the animal's tail would last long from the kind of impact needed to generate this noise. Even though it's a tail, it's still part of an animal's body. Whether it hits the ground and hits the predator, the tail's skin, muscles, and bones need to withstand that impact and I can't imagine such an impact would feel good for the sauropod itself. How many times can it be done before the tail is badly injured!? A whip is built to do this because it was specially made. It's also not part of the attacker's body. If you break a whip, you can always make a new one. You can't just grow a new tail tip. Not to mention constantly breaking it can't be a pleasant experience even if it can regrow the tail tip, which they can't.

The research published considered the first part of the whipping action, my little mind was focusing on the final impact of that action. The paper makes no mention of what would happen to the tail if it hits at that speed, but they really don't need to. The fact that the tail couldn't move at that speed, or survive moving at that speed is enough to tell you that the last part that I thought of wasn't important.

However, just because the tail can't be used to create scary cracking sounds to scare away predators doesn't mean it's not an effective weapon to defend itself from predators. Some of these tails are 12 meters long and weigh over a ton. Being smacked by that is no joke. It's still a good weapon to deter any theropod dumb enough to get close to it.