Wild Cat Found Mimicking Monkey Calls; Predatory Trickery Documented for the First Time in Wild Felids in Americas

Marguay (Leopardus wiedii). (Credit: iStockphoto/Jeff Grabert)

ScienceDaily (July 9, 2010) — In a fascinating example of vocal mimicry, researchers from the Wildlife Conservation Society (WCS) and UFAM (Federal University of Amazonas) have documented a wild cat species imitating the call of its intended victim: a small, squirrel-sized monkey known as a pied tamarin. This is the first recorded instance of a wild cat species in the Americas mimicking the calls of its prey.

The extraordinary behavior was recorded by researchers from the Wildlife Conservation Society and UFAM in the Amazonian forests of the Reserva Florestal Adolpho Ducke in Brazil. The observations confirmed what until now had been only anecdotal reports from Amazonian inhabitants of wild cat species — including jaguars and pumas — actually mimicking primates, agoutis, and other species in order to draw them within striking range.

The observations appear in the June issue of Neotropical Primates. The authors of the paper include: Fabiano de Oliveira Calleia of Projeto Sauim-de-Coleira/UFAM; Fabio Rohe of the Wildlife Conservation Society; and Marcelo Gordo of Projeto Sauim-de-Coleira/UFAM.

“Cats are known for their physical agility, but this vocal manipulation of prey species indicates a psychological cunning which merits further study,” said WCS researcher Fabio Rohe.

Researchers first recorded the incident in 2005 when a group of eight pied tamarins were feeding in a ficus tree. They then observed a margay emitting calls similar to those made by tamarin babies. This attracted the attention of a tamarin “sentinel,” which climbed down from the tree to investigate the sounds coming from a tangle of vines called lianas. While the sentinel monkey started vocalizing to warn the rest of the group of the strange calls, the monkeys were clearly confounded by these familiar vocalizations, choosing to investigate rather than flee. Four other tamarins climbed down to assess the nature of the calls. At that moment, a margay emerged from the foliage walking down the trunk of a tree in a squirrel-like fashion, jumping down and then moving towards the monkeys. Realizing the ruse, the sentinel screamed an alarm and sent the other tamarins fleeing.

While this specific instance of mimicry was unsuccessful, researchers were amazed at the ingenuity of the hunting strategy.

“This observation further proves the reliability of information obtained from Amazonian inhabitants,” said Dr. Avecita Chicchón, director of the Wildlife Conservation Society’s Latin America Program. “This means that accounts of jaguars and pumas using the same vocal mimicry to attract prey–but not yet recorded by scientists–also deserve investigation.”

WCS is currently monitoring populations of the pied tamarin — listed as “Endangered” on the IUCN’s Red List — and is seeking financial support to continue the study, which aims to protect this and other species from extinction. Next to Madagascar, the Amazon has the highest diversity of primates on Earth.

These behavioral insights also are indications of intact Amazon rainforest habitat. WCS works throughout the Amazon to evaluate the conservation importance of these rainforests, which have become increasingly threatened by development.

Wildlife Conservation Society (2010, July 9). Wild cat found mimicking monkey calls; Predatory trickery documented for the first time in wild felids in Americas. ScienceDaily. Retrieved July 30, 2010, from http://www.sciencedaily.com­ /releases/2010/07/100708141620.htm

Spitting Cobras Track First, Predict Later

Spitting cobra. (Credit: iStockphoto)

ScienceDaily (May 15, 2010) — Most venomous snakes are legendary for their lethal bites, but not all. Some spit defensively. Bruce Young, from the University of Massachusetts Lowell, explains that some cobras defend themselves by spraying debilitating venom into the eyes of an aggressor.

Getting the chance to work with spitting cobras in South Africa, Young took the opportunity to record the venom spray tracks aimed at his eyes. Protected by a sheet of Perspex, Young caught the trails of venom and two things struck him: how accurately the snakes aimed and that each track was unique. This puzzled Young. For a start the cobra’s fangs are fixed and they can’t change the size of the venom orifice, “so basic fluid dynamics would lead you to think that the pattern of the fluid should be fixed,” explains Young.
But Young had also noticed that the snakes ‘wiggled’ their heads just before letting fly. “The question became how do we reconcile those two things,” says Young, who publishes his discovery that the snakes initially track their victim’s movement and then switch to predicting where the victim is going to be 200 milliseconds in the future in the Journal of Experimental Biology.

Young remembers that Guido Westhoff had also noticed the spitting cobra’s “head wiggle,” so he and his research assistant, Melissa Boetig, traveled to Horst Bleckmann’s lab in the University of Bonn, Germany, to find out how spitting cobras fine-tune their venom spray. The team had to find out how a target provokes a cobra to spit, and Young was the man for that job, “I just put on the goggles and the cobras start spitting all over,” laughs Young.

Wearing a visor fitted with accelerometers to track his own head movements while Boetig and Westhoff filmed the cobra’s movements at 500 frames/s, Young stood in front of the animals and taunted them by weaving his head about. Over a period of 6 weeks, the team filmed over 100 spits before trying to discover why Young was so successful at provoking the snakes.

Analyzing Young’s movements, only one thing stood out; 200 ms before the snake spat, Young suddenly jerked his head. The team realized that Young’s head jerk was the spitting trigger. They reasoned that the snake must be tracking Young’s movements right up to the instant that he jerked his head and that it took a further 200 ms for the snake to react and fire off the venom.

But Young was still moving after triggering the snake into spitting and the snake can’t steer the stream of venom, so how was the cobra able to successfully hit Young’s eyes if it was aiming at a point where the target had been 200 ms previously? Realigning the data to the instant when Young jerked his head, the team compared all of the snakes’ head movements and noticed that the cobras were all moving in a similar way. They accelerated their heads in the same direction that Young’s eyes were moving. “Not only does it speed up but it predicts where I am going to be and then it patterns its venom in that area,” explains Young.

So spitting cobras defend themselves by initially tracking an aggressor’s movements. However, at the instant that an attacker triggers the cobra into spitting, the reptile switches to predicting where the attacker’s eyes will be 200 ms in the future and aims there to be sure that it hits its target.

Journal Reference:

1. Westhoff, G., Boetig, M., Bleckmann, H. and Young, B.A. Target tracking during venom ‘spitting’ by cobras. Journal of Experimental Biology, 2010; 213: 1797-1802