Newborn with a painless lump over the clavicle

Animals have evolved different strategies for excretion, the removal of waste from the body. Most waste must be dissolved in water to be excreted, so an animal’s excretory strategy directly affects its water balance.

Behavioral imprinting is observed in some newborn animals and occurs when they develop strong and specific attachments to another animal (usually a parent) following brief, early-life exposures. Offspring imprint onto parents within a brief period after birth or hatching; this time window is called the critical period. Once imprinting occurs, the bond established between the parents and their offspring is usually long-lasting.