Cambridge, Mass.
1910
Feb. 6 [February 6, 1910]
(No 4)
I am now referring the two bodies, looking and moving
as one, were alternately flattened against the trunk and
sprung out from it in a strongly outlined arch which
obviously touched the trunk at two points only. Thus
they swing out and in with rythmic [rhythmic]  pulsations until
the sensual ecstasy was over and the sexual act
finally accomplished. During its continuance I heard no
sound from either Squirrel. After it was ended they
separated at once and rambled off in different directions
through the branches of the elm. I do not recall ever
witnessing any act of cohabitation among the so-called
lower animals which has interested me so much as this.
While it was perhaps somewhat over-charged with salacious
suggestiveness it impressed me on the whole simply as
a natural and perfectly wholesome manifestation of admirable
sexual vigor on the part of two creatures engaged in a 
Gray
Squirrels
copulating