286 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1949 
both squirrels now do it regularly. Having learned the method, they 
usually hesitate after I have given them one nut to see if I will give 
them a second. Why make a trip home with only one nut when they 
can just as well carry two? The second squirrel to learn this is 
younger than the first one and may have observed the older one per- 
form the feat, for as pointed out elsewhere I believe animals learn 
much from observing others of their kind. However I saw the entire 
process of learning to do the act the first time with both of them, and 
thereafter it was a regular procedure to use the new accomplishment. 
Captive love birds (Agapornis) sometimes place straws under the upper 
tail coverts to transport them to the nesting site. 
My wife recently witnessed a novel method of transportation 
adopted by a yellowjacket (Vespula maculifrons). The bees were 
feeding on and carrying away pieces of raisins put on our fourth-floor 
window ledge for the birds. Generally they cut off a small piece of a 
raisin and never carried away a whole one, but she saw one bee roll a 
raisin with its head to the edge of the ledge and push it over. When 
the raisin started to fall, the bee followed it a short distance, then came 
back and repeated the process until it had dropped four raisins. My 
wife does not think the raisin was accidentally pushed over, as the 
bee’s movements seemed aimed at pushing it to the edge. Perhaps 
the nest was near the building and this bee had discovered an easy 
way of getting raisins to the nest. 
CARING FOR AND TEACHING THE YOUNG 
The type and amount of care and teaching that animal parents 
give the young varies from nothing to a very good education. Any 
consideration of this subject at once raises the question of how much 
the animal does by instinct and how much it learns from its parents 
or others. Of course, no conclusive or complete answer can be given 
to this, but there are many fragments of information that we can piece 
together to give us some light on the subject. Some animal mothers 
never see their young and give them no attention whatever. Among 
these are such animals as most snakes and lizards, which lay eggs that 
are hatched by the heat from the soil or from decaying vegetation, 
and the parent takes no part in their incubation. Exceptions are the 
pythons (Pythonidae) and skinks (Scincidae), which incubate their 
eggs, and the female alligator which stays near the nest to keep away 
intruders that might harm the eggs. However, the mothers take no 
part whatever in caring for or instructing the young. The mound- 
building birds of Australia and New Guinea (Megapodidae) do not 
incubate the eggs or care for the young; the mother lays the eggs in a 
mass of vegetation which she, together with other birds of the same 
species, scrape together, and in which all of them lay their eggs as in a 
sort of communal incubator. 
