Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Mammals and Litters
Name: Unknown
Status: student
Age: 15
Location: N/A
Country: N/A
Date: 2002

Why do some mammals have litters?

This has to do with survival of the fittest. Organisms that give no parental care, i.e. fish, frogs, have hundreds of offspring at a time. They abandon their eggs and the probability that only a few will survive to reproduce is great. Humans usually have only one child at a time and take very good care of them for a long time. Other mammals are closer to us, but they don't take care of their young for as long as we do. So they have more to insure that at least some will survive to reproduce.


The number of offspring is directly related to niche of the animal and the availablity of the mammals food supply. The higher the mammal is in the food chain, the smaller the number of offspring at a given time. Mammals sucha as rodents have to produce large numbers for most will not survive to reproduction age due to predators, so you have larger litters.

Steve Sample

Click here to return to the Zoology Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory