Belding's Ground Squirrel Research

Introduction

• Researcher: Jill Mateo, Ph.D., University of Chicago
• Location: Eastern Sierra, meadows, sagebrush, campgrounds
• Focus on Belding's ground squirrels, a highly social species

Life Cycle and Behavior

• Hibernation: Ground-dwelling species hibernate most of the year, active for 3-4 months in summer
• Mating: Occurs after hibernation; males compete fiercely for females
• Rearing of Young:
  • Females give birth to 5-8 pups
  • Pups are reared in underground natal burrows for about 25 days
  • High predation risk from snakes, weasels, and infanticidal squirrels
  • Mothers are protective, marking territories and warding off intruders

Juvenile Dispersal and Survival

• Juveniles face high predation risk upon emerging
• Survival Rates: Only 40-60% survive until fall
• Need to disperse from home, establish a hibernaculum, and accumulate body fat for hibernation
• Up to 60% may starve during the first winter
• Dispersal:
  • Males move 250-500 m away
  • Females remain near birthplace, close to relatives

Altruistic Behaviors

• Nepotism: Females engage in altruistic behaviors benefiting close kin
  • Alarm calls and cooperative defense of territories
  • Alarm calls increase predator risk to callers
  • Females defend territories of close kin more vigorously
• Males: Do not engage in nepotism as they do not live near close kin

Kin Recognition and Odor Cues

• Squirrels use odors from mouth and back glands to recognize relatives
• Kissing Behavior: Involves smelling oral-gland secretions to identify kin
• Kin Recognition: Enables nepotism based on degree of relatedness
• Comparison with Golden-Mantled Ground Squirrels:
  • Also produce kin odors but do not exhibit nepotism
  • May use kin-recognition to avoid inbreeding

Anti-Predator Behaviors

• Alarm Calls: Trill (mammalian predators) vs. Whistle (avian predators)
• Young squirrels learn appropriate responses after emerging aboveground
• Learning and Stress:
  • Stress levels affect learning; moderate stress may facilitate learning
  • Stress hormones measured non-invasively through feces
  • Highest stress hormone levels at emergence age, aiding in learning anti-predator responses
  • Higher stress at high-predation sites suggests influence on learning and development

Conclusion

• Belding's ground squirrels offer insights into social behavior, kin recognition, and learning under stress
• Observation of these behaviors can deepen understanding of adaptation and survival strategies.