come in heat

come in(to) heat

To be in a state of sexual excitement and able to breed, as of a female animal. Do you hear the stray cat howling and screeching at night? She must have come into heat.
See also: come, heat
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

come in(to) heat

 and come in(to) season
[for a female animal] to enter into the breeding season. This animal will come into heat in the spring. When did your dog come in season?
See also: come, heat
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
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