Burmese pythons CANNOT survive in cold temperatures. The Everglades got down to the low 40s recently. Most of the burms therefore must have died in the cold front. Although all of them likely didn't, logic has it that a majority did.

Proof:


GIVEN

t=Low Temperature for the year
b=# of burms in everglades
e=time temperatures were at t
t=38ºF
b=~4000
e=10 days

4000/{t[e(1/300)]}

According to this, 3158 pythons died during the cold front. Therefore only 842 pythons are alive in the Everglades.

The number of pythons is AN ESTIMATE. It may or may not be exactly correct.