Dear Shane,

tails are used for balance when climbing trees. Since bobcats and lynx, both belonging to the Lynx genus, primarily hunt on the ground and in fields for rodents and hares, they have not evolved with a long tail. This also helps in catching prey in open fields - a twitching long tail may alert the prey, in addition to larger carnivores of the bobcat's presence.

Best regards, Johannes

I don't know the answer to this but I've never seen an explanation that provides a convincing argument for a selective advantage. If I had to speculate, Id guess that a mutation arose in the common ancestor of the Lynx genus that produced a reduced tail; it was evolutionary 'neutral' ie provided no selective advantage or disadvantage, and was maintained in the lineage. Same for the Caracal lineage (all have somewhat reduced tails) and most of the extinct saber cat lineage that includes Megantereon and Smilodon. Until a compelling argument appears, Id argue that bob-tails have no selective advantage (or disadvantage).

I agree with Luke’s answer. Although Johannes’ answer seems plausible on the surface, that balance-tree hunting hypothesis is contradicted by multiple cat species that also primarily hunt on the ground but have long tails (eg, cheetahs, African lions, etc.).

Hello folks; Here is a single observation that might be interesting. I once observed five juvenile bobcats (young enough to still be wobbly on their feet) moving between hiding places. They were moving in single file. Each of them had their tail raised to a vertical position. The white undersurface of each tail was conspicuously visible to the individual immediately behind. They certainly looked like they were following a banner. Their mother was not nearby. A similar "follow the banner" behavior occurs in cheetahs when the mother is leading the young through tall grass. Whether the tail is short or long may be less functional that the visibility of the signal value of the "banner". Best regards, Jim Des Lauriers

Hi everyone, bob tails, big paws and very long hind legs might be a result of an evolutionary arms race between Lynx genus and their primary prey, lagomorphs. A bob tail can also be advantageous in very cold climates as it reduces the body surface and heat loss. In general, lynx are very light compared to their body size. So absence of tail might be also reducing the body weight which in turn prevents sinking in snow.

Bob-tailed domestic cats have the longer hind legs and higher rumps that are also characteristic of bobcats, lynxs and caracals. The short tails of the wild species may be a side effect of selection for longer, more powerful hind legs.

Maybe is just a handicap character.

Thank you to those who answered and shared this question. Although largely inconclusive—not that I had the expectation of resolution—I really enjoyed the answers. I am often surprised but also at the same time enthralled by obvious things before us that we still cannot explain. Moreover, I am too often guilty of falling into the adaptationist view. I should probably adapt a bit (my default thinking). Therefore, it was refreshing to read not only the adaptationists’ ad-hoc view on ‘why’ (which is what I asked), but it was also very welcomed to read the ‘how’ answer, which is to say—“maybe just because,” i.e., a mutation that provided neither an advantage nor disadvantage in terms of optimized fitness. Like a model carrying a ‘pretender variable’ high up the selection process, there certainly could be ‘pretender traits’. The tenets of natural selection are always good to review (at least for me). In any case, I hope others enjoyed the question and answers. Thanks a bunch! https://evolution-outreach.biomedcentral.com/articles/10.1007/s12052-009-0128-1

I also agree that hunting on the ground and thermoregulation theory does not explain this thoroughly for all the short-tailed cats (lynx, bobcat, caracal and servals). Moreover, Alexander Sliwa as far as I know, the predecessor (L. issiodorensis) of lynx and bobcat originate from Africa (so no cold environment was involved). One more theory to pond on: lynx, caracal and servals often JUMP straight up when catching their prey (birds, but lagomorph also jump up often to confuse the predator). Probably, the long tail is inhibiting these vertical jumps. In Iberian lynx, these jumps up are often observed. Maybe this is remnant of the L. issiodorensis hunting habits.

I was asked this question yesteray from a student in the class. I really didn't though this before and I speculated /replied that it seems to be an adaptation for ambush hunting and pursuing prey for short distances in closed forested areas. Movement and hunting in a forested and highly heterogenus habitat with rocks, fallen trees and bushy thickets could be a reason of not having a long tail that would probably be a disadvantage or at least a not so useful trait.

So... out of curiosity, I asked ChatGPT ~the same question in our brief discussion from a while ago. Interestingly, I think we covered all of the AI's responses.

Question:

Why do bobcats and lynx have short tails?

Answer:

Bobcats (Lynx rufus) and lynx (Lynx spp.), which are medium-sized wild cats native to North America and Eurasia respectively, are known for their relatively short tails compared to other cat species. There are several theories that attempt to explain the evolutionary reasons for the short tails in bobcats and lynx:

It's important to note that the exact reasons for why bobcats and lynx have short tails are still debated among scientists, and likely involve a combination of multiple factors. Evolution is a complex process, and multiple factors, including ecological, physiological, and genetic factors, can interact to shape the physical characteristics of animals, including their tail length. Further research and study are needed to gain a more comprehensive understanding of the evolutionary reasons for the short tails in bobcats and lynx.