Which of the following is an example of a Type II survivorship curve species?

• A. Humans
• B. Rodents
• C. Spiders
• D. Elephants

Answer: (B)

Type II survivorship means the chance of dying is about the same at any age, so the number of survivors declines at a steady, almost straight-line rate as time passes.

Rodents fit this pattern because their mortality risks are fairly constant across life stages—predation, disease, and other hazards affect individuals similarly whether they’re young or older, leading to a relatively linear decrease in survivors over time.

Humans and elephants, in contrast, typically show Type I survivorship: most survive to a relatively old age with high juvenile survival, and mortality rises mainly at older ages. Spiders can exhibit Type III patterns too, with high juvenile mortality and many offspring, not a constant hazard across ages.