Some scientists theorize that this behavior developed from thetactic of throwing

Question

Some scientists theorize that this behavior developed from thetactic of throwing smaller eggs to break them open. Ostrich eggs,however, are too big to pick up and throw, so perhaps therock-throwing technique evolved in the vultures. This could explainwhy vultures choose rocks that are egg-shaped, rather than onesthat are jagged or irregular.

The shape of the rock that the vultures chooseis modified by their experience. Egyptian vultures must imprint on their ownspecies in order to crack eggs using rocks. Questioning whether the rock-throwing behaviorarose from egg-throwing relates to ultimate causation. Rock-throwing in vultures is an innatebehavior. Examining the anatomical mechanism that enablesEgyptian vultures to throw rocks relates to proximatecausation. In Egyptian vultures, eating ostrich eggs is alearned behavior. Pecking at eggs to break them open is anexample of tool use.

Explanation / Answer

An Egyptian vulture, Neophron percnopterus, hasbeen observed breaking open ostrich eggs, too hard to open bypecking, by throwing a stone held in its beak at the egg shell. Thebird's aim is quite good. According to reports by Jane Goodall, thevultures will wander as far as 50 meters (165 feet) from the egg tofind a suitable rock.

The rock most often chosen is an egg shaped. This suggests that thevultures have modified an earlier behavior. Many birds throw ordrop eggs to break them. John Alcock has suggested that thevultures originally threw or dropped eggs to break them open.The use of rocks to break the eggs openprobably began when a vulture accidentally hit an egg with a rock.They then evolved from throwing the eggs to throwing rocks at theeggs. The movement the vulture makes when breaking an eggwith a stone is almost the same as the movement the vulture makeswhen pecking at an egg to break it.

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.