Rainforests can be called the laboratories of life. Over half of all plant and animal species are found in these eco-systems that occupy less than 6% of the Earth’s area. Some of the animals have evolved to hunt and feed on other animals and are called predators. They are an important cog in the circle of life as they control prey populations thereby maintaining an ecological balance.
It’s not an easy co-existence, however. Prey species continuously adapt to stay one step ahead of the predators. And predators need to maintain the pace so that they get to their next meal. As species evolve, their strategies get increasingly intriguing.
Most rainforest predators hunt solitarily, possibly due to the difficulty in communicating in the dense forest. They follow two broad strategies:
- Active Foraging and Stalking prey, using thick cover to their advantage
- “Sit and Wait” for prey to walk in on them
Some animals, like ants, hunt in large groups with a third strategy – Legionary Behaviour.
Mammalian predators like tigers, leopards and dholes roam the rainforests of the Western Ghats (typically following a foraging and stalking strategy). Birds – from the spectacular Great Hornbill to the mighty Black Eagle to the tiny Speckled Piculet – have a wide range of diet preferences. Here, we look at the lesser-noticed, yet ubiquitous predators of these forests.
Predatory Strategy – Active Foraging and Stalking
A Choosy King – Some predators are very specialized in their diet, like the King Cobra (Ophiophagus hannah). The longest venomous snake in the world (reaching over 15 feet in length in the Western Ghats) feeds almost exclusively on other snakes, occasionally gobbling up Monitor Lizards. In fact, the genus of the King Cobra – Ophiophagus – means snake-eater in Latin.
Death by Camouflage – The unlucky frog (Indirana sp.) didn’t realise that it was being carefully stalked by the master of camouflage – the Common Vine Snake (Ahaetulla nasuta). The snake carefully takes its time to assess its prey before swiftly moving in for the kill; all the while mimicking a vine in the forest, even moving side to side as if swaying gently in the wind!
Legs – As if to compensate for the limbless snakes in the rainforest, centipedes have an excess of legs. Scutigera species can have upto 15 pairs of legs, with the first pair of legs modified into forcipules that inject venom into the prey. They are the only order of centipedes that have retained their compound eyes. Typically nocturnal, they seem to rely on their long antenna to hunt insects and arachnids.
Hunters with a 360-degree view – 8 eyes, placed strategically on their heads, give the Jumping Spiders (family Salticidae) amazing vision. Combined with the ability to jump several times their body length, Jumping Spiders are formidable predators in the undergrowth. They are known to bring down prey that is much larger than them and administer fast-acting venom to immobilise it.
Running Champions – Imagine running at 350 kmph. Well, that’s how fast a Tiger Beetle would run if it were the size of a human! Tiger Beetles are the fastest running insects in the world, clocking speeds upto 9 mph (or 125 body lengths per second). Their huge eyes give them excellent eyesight to find their prey. They have prominent mandibles that help them hold onto their prey and, in the case of males, to the females during mating. And their glossy wings (often brightly coloured) are a treat to behold.
Mother with Foresight – Predators don’t necessarily hunt for themselves. Some wasps paralyze much larger spiders and drag them into a hole in the ground. They lay their eggs on the spider, seal the hole and fly away. As the wasp larvae emerge, they have fresh food available (remember, the spider was only paralyzed) for their first meal.
Predatory Strategy – “Sit and Wait”
Welcome to my lair – Spiders are known for their intricate webs. Some, like the Funnel Web Spider (Hippasa sp.), build their webs close to the ground in the shape of a funnel and wait for unsuspecting prey to walk in. Others, like the Signature Spider (Argiope sp.), spin elaborate webs between plants or trees that are designed to capture flying insects as well.
Patience Unlimited – Endemic to the Western Ghats, the multi-morphed Malabar Pit Viper (Trimeresurus malabaricus) is a virtuoso of the waiting game. These Pit Vipers are known to stay around the same place for several days at a time, before their next meal comes by. All along, they mostly stay motionless, only moving to shift into a more comfortable pose or slither a short distance to a safe place to get some sleep. Heat-sensing pits located between their eyes and nostrils help them detect and judge the size of their prey even in the dark.
False Alarm – Not all that passes by is prey though. A Malabar Pit Viper suddenly gets attentive due to a slow and gentle approach – by a snail. Soon enough though, the snake seems to lose interest in the snail. So much that the snail literally tramples all over the snake and goes away! Possibly the shell seemed a bit daunting.
Praying for its Prey – At first glance, the folded forelimbs of the Praying Mantis seem to suggest just that. It is actually ready to grab on to the next unsuspecting prey that walks too close to it. The triangular head with the large eyes gives it a 180-degree vision. And the “hooks” on the forelimbs are designed to hold onto even the most persistent of its prey.
Aerial threat – Robberflies. Assassin Flies. The names seem apt for these insects (family Asilidae belonging to the order of true flies – Diptera) that are known to wait at a suitable perch and launch aerial sorties to catch unsuspecting prey in flight. And it’s not just tiny beetles that they go after. Robberflies have been known to feed on much larger insects like dragonflies, grasshoppers, and even other robberflies!
Opportunists everywhere – From water bodies and streams to the forest floor to the canopy, frogs are found everywhere, like this Bush Frog (Pseudophilatus sp.), and they wait patiently for their prey. Some frogs shoot out their spring-like sticky tongue to catch hold of flying insects. Others stuff prey into their mouths with their forelimbs.
Predatory Strategy – Legionary Behaviour
An Army Marches – Very few rainforest predators have evolved to hunt in groups. None of them is probably as formidable as an army of ants. With trails over 100m long, some species are known to consume over 500,000 prey animals in a single day!