1. Ground squirrels, rattlesnakes, and burrowing owls: the legend of the “happy family” Matthew Rowe Michigan State University

2. My goals this morning….. ✓ share… critters and questions ✓ demonstrate… sophisticated interactions ✓ convince… deserve our admiration ✓ inspire… a love of asking questions

3. Illustration by Ernest Thompson Seton The legend of the ‘happy family’

6. Squirrels vs. snakes: the California players California ground squirrels (Spermophilus beecheyi) Northern Pacific rattlesnakes (Crotalus oreganus) Photo by John CookePhoto by Ron Swaisgood

7. Squirrels vs. snakes: the New Mexico players Rock squirrels (S. variegatus) Western diamonbacks (C. atrox) Photo by Larry Rabin Photo by Wayne Van Devender

8. Squirrels at both sites do have other predators, including other snakes… Photo by Franco Folini

9. Background “stats” Rattlesnakes - principal predators of ground squirrel pups Adult squirrels - resistant to rattlesnake venom and, thus, are assertive in protecting pups So, rattlesnakes and adult ground squirrels are adversaries Consequently, squirrel-rattlesnake encounters are similar to a “boxing match” With associated opportunities for probing & assessment

10. When a snake is detected in a colony….

13. Snakes respond defensively to ground squirrel confrontation -- -- can include rattling and striking

14. Why work so hard to induce the rattlesnake to rattle? Photo by NGS/Chris Johns

17. Photo by Edward Rooks Photographer unknown

19. Evidence that smaller rattlesnakes are more vulnerable than larger rattlesnakes

20. Evidence that warm rattlesnakes are more dangerous than cold ones

23. Cues in rattling associated with rattlesnake body size

24. Cues in rattling associated with rattlesnake body temperature

25. Click rate – another view

28. Squirrels use size and temperature cues in rattling

29. Ground squirrels make subtle assessments about risk

30. Squirrels mediate their risk in other ways -- -- by transferring their young to other burrows -- by anointing with snake scent

31. What is the function of snake-scent anointing (SSA)?

32. Functional hypotheses of SSA 1. Antipredator 2. Ectoparasite defense 3. Conspecific deterrence

33. 2. Ectoparasite defense SSA repels fleas Test: flea host choice

34. 3. Conspecific deterrence SSA deters rivals Test: compare fights before & after SSA

35. 1. Antipredator SSA disguises squirrel odor  Test: compare rattlesnake foraging behavior

36. What about burrowing owls?

37. Illustration by Ernest Thompson Seton The ‘happy family’ revisited

38. Special thanks:

39. What are we doing now?

40. Looking for a few good teachers!

41. Thanks!