Tiger talk

Abstract

Roaring, growling, snarling, snorting – fine. But why would a tiger (Panthera tigris) make a sound like a frightened sambar deer (Rusa unicolor)? (compare recordings at https://bit.ly/2CVLJiu and https://bit.ly/2H1gbMm). It's not the kind of thing you would expect from a tiger, yet this “pooking” call, as it is known, has regularly popped up in the literature as being made by Bengal tigers (Figure 1) for over 100 years. Following the investigations of renowned naturalist George Schaller, it became generally accepted that tigers pook to warn other tigers (and possibly even humans) of their presence, and thus avoid unexpected encounters (Schaller G. 1967. The Deer and the Tiger, A Study of Wildlife in India. Chicago, IL: University of Chicago Press). Alternatively, some suggest it may be a location call, perhaps between mates. Hunters in India, however, have long held that tigers pook to attract sambar deer. Crazy, right? Well, I thought so too, until I discovered that margays (Leopardus wiedii), small cats found in Central and South America, get up to similar antics. And you thought they only roared! V Hawargi; CC BY 2.0 In October 2005, researchers working in the Adolpho Ducke Forest Reserve (Manaus, Brazil) recorded how a margay played a trick on a group of pied tamarins (Saguinus bicolor). Hidden in the vegetation, the little feline began to make calls that attracted the sentinel tamarin's attention: the calls of a pied tamarin youngster! Taking the sounds to be genuine, the sentinel ran up and down a liana to see who was making them, letting out warning calls to inform the troop of the supposed intruder. Eventually, four tamarins started to investigate. Encouraged, the cat approached the primates from its hiding place, ready to spring its trap. But while the margay secured itself a place in the scientific literature that day (Neotropical Primates 2009; 16: 32–34), it did not secure itself a tamarin. The ever-watchful sentinel spotted it, let out a scream, and the little band of monkeys ran off. Then came more surprises. For centuries, the northern shrike (Lanius borealis [ex L escubitor]), a predatory songbird, has been rumored to mimic the songs of its passerine prey species. Certainly, some North American northern shrikes are said to copy, at least in part, the alarm calls of chickadees (Poecile spp) and nuthatches (Sitta spp). Then, in 1997, the shrike's winter song was scientifically shown to attract the singer's dinner (Condor 1997; 99: 203–06). Several types of small bird came to inspect a recorder playing the song, and they were also seen to approach real shrikes showing off their impersonation skills. The predators summarily dispatched them, their performances truly knocking ‘em dead. Australia's grey butcherbird (Cracticus torquatus) may also lure small birds with a song containing deadly lines copied from silvereyes (Zosterops lateralis) and brown thornbills (Acanthiza pusilla) (Emu 1930; 30: 62–63). And in Panama, three forest-dwelling falcon species of the genus Micrastur apparently also make vocalizations designed to induce reactions in prey species. Desperately trying to pinpoint the location of the predator, and even maybe mob it, the prey birds move about – a fatal mistake (Ibis 1969; 111: 241–43). But what about those Bengal tigers? In fact, some stories suggest that they may also acoustically attract chital deer (Axis axis) (Montgomery S. 1998. Spell of the Tiger: The Man-eaters of the Sundarbans. White River Junction, VT: Chelsea Green Publishing). Siberian tigers are said to lure their local deer too – and perhaps even Asiatic black bears (Ursus thibetanus) – by imitating their sounds. “In Russia, many hunters believe that tigers imitate the mating call of male red deer during the mating season to attract other deer”, confirms John Goodrich, Senior Director of the tiger program for Panthera, a wild-cat conservation organization (New York, NY). But a pook sounds like a sambar deer's alarm call. Surely, no deer would approach an alarm call. So, are pooking tigers just broadcasting their presence, or could this sound be designed to make a stationary deer react, rendering it detectable? Well, perhaps it's both. “For the most part, pooking is a way to establish territory and communicate with other tigers”, explains Courtney Dunn, Executive Director of the Prusten Project (www.theprustenproject.org), a conservation initiative that has been investigating tiger vocalizations. “A pook may travel five kilometers, and you can tell who the individual tiger is from the frequency. As for pooking for attracting or finding deer, I'd say it's very plausible. [These false] calls would be relayed by other sambar, giving their locations away.” So, next time you are out and about in the depths of some Asian forest and you hear what you think is the frightened call of a sambar deer, maybe you should just sit tight for a while. For who is to say it is not the ploy of a sneaky tiger looking for his lunch?