In the “Would you get your son’s penis circumcised?” thread, ZPG Zealot writes that one key difference between humans and animals, according to some, is our ability to actively change our bodies beyond what we were born with. Link.
Is this true? Or are there certain species that knowingly and willfully modify their bodies? I’m not talking about a hermit crab who finds a shell for a home (external clothing) or a frog that’s able to change sex over time (I don’t think that’s “knowing and willful”). Nor do I mean the practice of “docking” an animal by its owner. But is there an animal equivalent to ear piercings, tattoos, circumcision, haircuts or even “working out to lose weight/beef up” that the animal performs on itself or other animals?
I don’t think antler shedding would qualify - there is no real choice in the matter. Perhaps male birds preening to enhance the plumage for courtship is in the outer edge of the OPs conditions. An octopus or lizard changing it’s color/texture is not a permanent alteration so that may not qualify either.
A great many animals modify their teeth and nails. Pigs sharpen their tusks by rubbing them against their other tusks and objects. Rodents gnaw to adjust the blade and length of their tusks. Most animals will scratch to adjust the length and sharpness of their claws.
There are certainly plenty of captive animals that engage in behaviours such as feather plucking or chewing that results in permanent modification including scarring, but because they are animals we consider such behaviours to be destructive and evidence of psychological disorders. However this seems like an obvious inconsistency, if we then say that it is not destructive or evidence of psychological disorder for humans to mutilate their genitals because an invisible sky pixie tells them to.
The [white tailed] deer antlers are covered with a living skin called “velvet” while they are growing. (Antlers are grown and shed every year.) This velvet supplies blood and nutrients to the antlers, which are bone. At some point in time, the blood supply to the velvet is cut off, and the velvet dies. The deer end up scraping off this velvet on handy trees or whatever. cite
Do they do this because the velvet is annoying? Unsightly? I don’t know. Sure, it’s not a concious thought process, but they don’t let the velvet just hang there, either.
Animals that preen their feathers (or whatever) for mating season are doing it instinctually, too.
Interesting. This info says that “rubbing is largely a behavioral response to increasing testosterone, which stimulates the animal’s preoccupation with scent marking and his sexuality. I recently watched a buck engaged in “rub out” removal of velvet…”.
So there you have it – it’s all about sex and the male of the species “rubbing one out.”
There’s the old legend that a coyote will chew off its leg to get out of a trap… Which explains Franco.
(Also gives rise to the expression “coyote f*ck”. You wake over the next morning hung over and your arm is trapped underneath her, but she’s so ugly you chew off your arm to get away before she wakes…")
I don’t have specific video or photos of them doing it, if that’s what you’re asking. Queen ants have wings on their mating flight, then after mating when they’re ready to start a new nest, they land and pull off their wings - biting them off or rubbing them with their legs until they break off.
I don’t think they eat the shed wings. It’s more likely that the wings would get in the way when living underground.
The decorator crab is another crab-related example. They glue pieces of seaweed to their shells for camouflage. (And, judging by the pictures, anemones as well).
The stalk-eyed fly. Males, upon adulthood, before their bodies harden after exiting the pupae shell, will pump air into their stalks so that their eyes are as wide apart as possible.
Male cuttlefish flash strobing stripe patterns down their bodies to compete with other males. It’s a use of a neuro-coloring system that they’re born with, but it’s a purposeful change and the one that can modify himself best is the winner. The also change to hide and to attract mates.
Some smaller males color down and make themselves look more like a female. It allows them to slip into groups of females that the larger males are flasing for. Gene tests have shown that it’s an effective strategy.
ZPG Zealot writes that one key difference between humans and animals, according to some, is our ability to actively change our bodies beyond what we were born with. Link.
I think that is an astute observation about something fundamental to being human, and it raises really interesting questions.
But to your specific question: the real nut of it is whether any other animal intentionally removes functional tissue from its own body for no functional purpose, like humans do. If there were going to be an example, I’d expect it from the ants, since they invented so many “human” institutions (agriculture, animal husbandry, food storage, warfare, central heating, etc.). The queen ant wings suggested by one poster are the closest example here, I think, but there is a good reason for that: transitioning to a life stage in a new environment where wings are nothing but a liability.
The suggestion that the self-mutilation seen in captive animals might relate to humans is a really fascinating idea that raises questions about individual human adaptation to society.
I recently found modified snail shells while out walking in the bush. Oddly, they were all missing their tips. Turns out that predatory Rumina decollata snails intentionally grind away these tips for unknown reasons–this seems to be perfectly functional tissue, and the snails live in the open. This is the only example I can come up with that would seem to offer what you are looking for: animals modifying their bodies to no obvious benefit.