A Little Bit More
Most mammals are quite helpless at birth – often hairless, with closed eyes and perhaps even with their external ear canals sealed for a time. Many rodents aren’t covered with fur until they’re at least one week old and their eyes may not open until the 10th or even 20th day after birth. Bears have a particularly short gestation (pregnancy). Baby cubs are only about 280-340g (10-12oz) at birth while some of the marsupials like kangaroos and Opossum have even shorter gestation periods and babies that have mere stumps where appendages will eventually be.
At the other extreme are animals like horses, cows, bison, antelope, and deer. These animals live nomadic lives and are in constant danger of being captured by large carnivores (at least they used to be!). Young of these mammals are usually very well-developed, alert and able to keep up with their mothers soon after birth. Bison calves can follow their mothers within hours after birth and a 4 day-old Pronghorn can outrun a human! Deer are not as nomadic as Bison and their young take a bit longer before they’re following their mothers. At first fawns remain hidden during much of the day while their mothers feed and are together only when it’s time to nurse.
One interesting aspect of birth and infancy for humans is the fact that we’ve become so removed from a “natural” birth process that we hardly know what it’s all about. Today’s typical North American first-time mother has never seen a birth and probably only has a vague idea of what birth is really like. All other mammals go the “natural” route and seem to do just fine.
Activities
Science – Ask a relative
Objectives: Better idea of human infant development
Materials: Access to relative
As a human baby develops, there are many benchmarks of their growth. These benchmarks include rolling over, making eye contact, smiling, crawling, walking, and first words. Have your students take a list of human developmental benchmarks to one of their relatives and see if they can find out when they attained these themselves. Granted, many parents/relatives won’t remember each and every one of these but some will.
Once a student has some ages for their own developmental benchmarks they can return to class and share these with other students. I think many will find that there will be “general” agreement on many of these benchmarks but there will be variations too. It should be stressed that an early walker, for example, is no more likely to be an Olympic star than one who walked later in his/her development – this isn’t a contest.
This exercise should NOT be used as competition among the students.
Some questions you may want to pursue:
1. Why might some babies walk at an earlier age than others?
2. In your class, are there any boy-girl differences in the times when developmental benchmarks are achieved?
3. Most children begin first grade at age 6. Does it make sense that ALL children are ready for school at this age?
4. If there are developmental benchmarks in infancy, might there also be benchmarks in later years such as 16-18 year olds?
Key Concepts
Adaptations and Diversity, Behavior and Regulation, Growth and Development, Life Cycles
Questions
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