Parasites and Diseases
Nose Bots

A Field Guide


caption follows
Caribou throat with two nose bots.

What causes nose bots?
  • This condition is caused by the larvae of the bot fly.
  • Lifecycle: The adult female bot fly deposits larvae in the nostrils of caribou. Nose bot larvae attach and grow in a cluster in the caribou’s throat near the base of the tongue. The larvae are sneezed out in the spring.

Where are nose bots found?
  • Nose bots can be found in caribou throughout their range in Alaska.

What are the signs of nose bots?
  • Caribou usually appear healthy.
  • When laying their eggs, bot flies harass caribou and interfere with feeding.
  • Nose bot larvae are found in the sinuses and airways at the back of the throat.
  • The worm-like larvae are white when they begin to develop but grow to ¾ to 1½ inches in length over the winter and become yellowish-brown.

How can I protect myself?
  • You cannot be infected by nose bot flies or their larvae.

Can I eat the meat?
  • Meat from affected animals is suitable for human consumption.

Samples to collect
  • Larvae of the bot fly
  • To report an occurrence or to submit a sample for identification/analysis, contact the DWC Wildlife Disease Surveillance reporting hotline 907-328-8354, send an email to or visit your local ADF&G office.