Wednesday, Nov 26, 2014

How nature plots and plans to fool predators

Written by Ranjit Lal | New Delhi | Posted: June 1, 2014 5:00 am | Updated: June 1, 2014 3:49 am
Are the games that nature plays to fool predators  really well thought out? Are the games that nature plays to fool predators
really well thought out?

I have often wondered if nature plots and plans and (as we love saying) “strategises” with Machiavellian cunning to get her way. The creepiest examples of these have to do with camouflage, defence and mimicry. Innumerable species of mammals, birds, insects, fish et al are cunningly clad so that they completely blend into their ecosystems (the tiger is a classic example). Some go a step further by pretending to be dangerous and venomous by mimicking relatives that are — butterflies provide good examples of this. Evolution tells us that this has all happened by chance over millennia, but it does make you wonder: is there some great evil genius at work here, plotting its moves step by step?

Fortunately (or not!), there do seem to be inconsistencies that crop up in nature’s “logic”, where matters do not seem to have been taken to their natural conclusion. Take “playing dead”, for example. When attacked, some creatures simply roll over and play dead, hoping their attacker will leave them and go away. I’ve rescued stunned black kite fledglings that have done this; some snakes are also known to do this. If they’re hoping that their predator will leave them and not eat them, thinking they’re dead and rotten, they might have to think again. Some predators are only too happy to feast on already dead (and often maggot-infested) prey. So that’s a big gamble that they’re taking. You might think that when they flop down “dead”, the predator will relax its grip on them, giving them a chance to break loose and scuttle away (rather like a lizard dropping its tail), but at least in the case of the kite fledglings this did not happen. They waited until I had (suspecting some hanky panky) laid them down in the garden and went indoors: then they came miraculously alive again and hopped off towards a hedge. But, surely, if they had “played dead” with a cat, they would have ended up really dead and in the cat’s tummy… The fact that they still do this means, perhaps, that they have a better chance of surviving, though it still doesn’t make logical sense.

Take red-wattled lapwings as another example, in a different sort of way. These leggy bronze birds usually lay four perfectly camouflaged eggs amidst clods of earth or rocks and stones. The parent birds (which must be the most neurotic in the avian kingdom), however, will not let you get anywhere close to the nest — they’ll launch an all-out dive-bombing attack, screaming accusingly (“Did-he-do-it? Did-he-do it”!), and drive you away. Now this may divert, say, cattle that could trample the eggs, but surely canny predators like a pack of stray dogs will cotton on and dodge the bombardment and winkle it out…

I can only guess that continued…

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