Location: The Arctic National Wildlife Refuge: 1002 calving grounds of the Porcupine Caribou herd

The 2005 spring season in the 1002 found a heavier than normal snow-pack. While significant numbers of caribou calved outside the 1002, subsequent movement and behavior took place as usual save a significant exception: the cool and snowbound arctic spring of 2005 brought the remarkable event of NO MOSQUITOES!!

Following the week-long build up and unexplained panic flights of several hundred caribou, (cows and calves of the Porcupine herd), individual animals were witnessed in display of "mad caribou syndrome": the seemingly inexplicable behavior of wild and senseless running in circles, back and forth, general movements of "crazy activity". In any other year, the panic flights and mad behavior would have been either attributed to mosquitoes or simply left unexplained.

In close observation of single animals in panic (wild behavior), it became apparent that these animals responded as if being assailed and harassed. No mosquitoes, no pests, no accountable predators yet still the caribou massed in panic flight. A seemingly invisible attacker harassed and drove these animals to desperate flight.

Invisible ... yes, imaginary ... no.

The initial phase of this invisible attack upon the caribou took place the previous summer (2004) when the adult Warble Fly deposited its' eggs upon the caribou's fur. The second phase of the attack occurred as the eggs hatched and the Warble Fly larvae invaded the body of the caribou. Throughout the ensuing year, feeding upon its' host and growing larger, the developing larvae remained inside the caribou's body,

June 17, 2005 ... the 2004 Warble Fly larvae have now sufficiently matured to emerge from within the caribou and drop to the ground; (once upon the tundra, the Warble Fly larvae completes its' life cycle to emerge as an adult Warble Fly; the cycle repeats). Emergence from the caribou entails the now enlarged larvae to wriggle out through the small breathing hole previously chewed into the caribou's hide. The large grub forcing its' way through the small opening in the caribou's flesh, causes the animal discomfort and is most likely, painful.

Upon the sense of this "attack from within", the caribou thrash about in panic and flee as if the assault could be evaded. The assault follows the animal until the larvae drop to the ground. It is an instinctive reaction for the herd to sense the danger signaled of a single member of the group. A single frantic animal can and does panic entire herds of caribou. These stampeded groups travel a distance deemed safe from their pursuer then stop to assess their position; no predators in sight, they return to grazing, resting and caring for their calves. There is no sign of their attacker, there is no movement of predator in stalk of their flesh. The Warble Fly larvae lays hidden on the ground, its' presence invisible until the adult fly takes to the wing.