Living in a group offers many opportunities to an animal, but is can also lead to some incredibly strange (and in some cases, weirdly human) behavior. Let's take a look at how...
- Chimpanzee warfare uses human tactics
- Some ant colonies make false floors and living traps
- Degu society is urine-based
- Locusts swarm to avoid cannibalism
- Some penguins and monkeys become prostitutes
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| Capuchin monkeys have been observed "paying" for ex in the lab... (Wildfaces) |
Chimpanzee Warfare Uses Human Tactics
Few animals conduct warfare like humans - but chimpanzee territorial disputes are disturbingly similar to human conflict. Much of our insight into this comes from the 4-year long Gombe chimpanzee war, fought between the Kasakela and Kahama colonies in 1974.
The conflict began with the ambush killing of a Kahama male, followed by a further six males over four years. During this time a pair of Kahama females also went missing, with another three being beaten by raiding parties. Eventually the Kasakela group drove the Kahama out... only to be chased off by a a third colony.
Similar situations have been observed in Uganda, where researchers noted a pattern of patrols, ambushes and assassinations that wouldn't have look out of place in a human military. The apes have also been observed using surveillance tactics, observing rival territory from high ground then sneaking in when the coast seems clear.
Some Ant Colonies make False Floors and Living Traps
Ants are one of the more cooperation-focused members of the animal kingdom, but the Amazonian Allomerus decemarticulatus take things to a sinister new level - they set up living pit-trap, torture-rack and butcher-block combos worthy of a slasher film.
The ants clip hairs from the stem of their chosen plant, leaving just enough to act as a scaffold. They then weave a platform using the harvested hairs and fungus, boring small holes (just enough to stick their heads through) through the finished structure. The ants then retreat into their creation, lurking just inside the holes and waiting for prey.
When an unfortunate insect puts an errant leg in one of the holes, the ant inside grabs it and hangs on. Each movement that brings the victim into contact with the platform results in another grabbed appendage, leaving the prey stretched across the surface as though bound to a sacrificial stone. Workers then flood out and bite the trapped victim to paralyze them, before carrying the prey to the nest... or dismembering them for ease of transport.
Degu Society is Urine-Based
Reaching around 30cm, the common degu looks a lot like an overgrown hamster - albeit one that can shed its tail as a one-time escape mechanism. They make their communal burrows in the sandy soil of Chile, while relying on urine to bind their society together.
The degu uses urine to scent-mark trails and territory, but that's not all. Degu urine reflects ultraviolet light, which the rodent can see. Because the strength of reflection is affected by freshness, a degu can tell how old a urine patch is and thus identify "social hotspots." They even bathe by rolling in urine-soaked sand... perhaps this provides them with a glowing coat in the vision of their comrades?
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| Researchers believe that swarming helps locusts avoid being cannibalized... (christels) |
Locusts Swarm to Avoid Cannibalism
Locusts are one of the few animals that get labelled a plague - but have you ever wondered what drives their swarms? When locust populations reach a certain density, they begin to mobilize - this density normally occurs when food is scarce and the insects have to crowd into the same territory.
One fun fact about locusts is that they are habitual cannibals. Being bunched up in the same territory massively increases the odds of being eaten by their neighbors... but swarming can help the insects survive. Researchers have calculated that the orderly movement of a swarm - chasing the locust ahead of you while fleeing the one behind - minimizes the chances of direct contact with another locust. Swarming allows the insects to avoid being cannibalized while seeking out new food.
Some Penguins and Monkeys Become Prostitutes
Sometimes called the oldest profession in the world, prostitution has occurred throughout human history... but it seems that some animals turn tricks as well.
Adélie penguins use stones to build their nests - the reason for this becomes apparent in spring, when meltwater streams through their nesting site. A high platform of stones will keep the eggs safely out of the water when a "normal" nest would drown. Building a big enough nest requires a lot of material however, meaning that there is a very high demand for good stones... so a few penguins have turned to unorthodox tactics.
Some female penguins will wait until their mate has headed off to catch food or hunt stones, then go on the prowl. They typically target single males (targeting mated males usually results in being attacked by their partner) and initiate courtship behavior with them. Sometimes the female copulates with the male and sometimes she doesn't, but in either case she snags a stone from those collected by the male and leaves without being attacked. One female in particular was observed getting 62 stones from a luckless male, all without "sealing the deal" as it were.
Penguins are not the only animals to dabble in prostitution - transactional sex has been observed in a capuchin monkey token-economy study at Yale. A token economy is a simple psychological set up - subjects are given a token (a shiny metal disk, in this case) for doing a task that they can hand to an experimenter for a reward - usually a choice of foods. In this particular study the capuchins had figured out that the tokens could be exchanged for treats. They were also able to suss out the best value deals for their tokens.
With basic economics sorted, it wasn't long before the monkeys moved on to vice. Usually researchers lured a monkey into a "test chamber" attached to their enclosure for each experiment. One fateful day, the chosen monkey grabbed the tray of tokens in the test chamber, hurled it into the main enclosure and scampered after it - a monkey bank heist. To make matters even more surreal, researchers observed a male monkey giving a token to a female in exchange for sex. The female traded the token for a grape as soon as the deed was done!
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