Fawns in the first week after birth exhibit alarm bradycardia (the heart rate decreases quickly to aid in the “freezing” response) to avoid detection by predators. They also are virtually scentless after birth to help them avoid predators, but they gain scent as they age.
Activity of fawns during the first week of life consists of nursing and moving between bedding sites, which accounts for only 3% of their time. They sleep and rest the remainder of the time. By 9 weeks of age, fawns are active 27% of the day.
The fawn and mother make sounds and use the sense of smell to help locate each other. If the fawn is threatened, the female snorts and stamps her front feet and may charge the predator to drive it away. As the fawn grows and gets stronger, it begins following the female as she forages.
Fawns nurse an average of twice daily. As the fawns age, the time spent nursing increases, but the frequency does not.
Fawns must have microorganisms in their rumen to break down the vegetative matter they consume. For their first month they live exclusively on milk. After a month or so, fawns begin to eat grasses, tender woody vegetation, and even shelled corn. At times, the female will drive a fawn away that still wants to suckle after attaining the age of 5 to 6 months.
Small fawns are unafraid of humans. Until they are 4 or 5 days old, they will not attempt to escape when detected. It is at this stage that most deer fawns are taken alive illegally because they are mistaken for orphans. Sometimes, fawns end up in strange places, such as on sunny porch steps. If you find a fawn by itself, do not move it. The mother is usually nearby, though not necessarily in sight. She will return to the fawn twice a day so that it can nurse.
n one Illinois study, 121 females produced 221 fawns (102 females, 119 males) that survived to at least one year old. Among these 221 fawns, 35 (29%) birth events produced single fawns, 78 (63%) produced twins, and 10 (8%) produced triplets. It is possible for a pregnant doe to have four or five fawns, but it is very uncommon.
For midwestern states, the percent of fawns that became pregnant ranged from 2% (Minnesota) to 29% (Iowa to Nebraska). For yearlings, the range was 55% (Iowa to Nebraska) to 88% (Minnesota). For adults, the pregnancy rates varied from 71% to 96% (multiple states). Contrary to what was once believed, females never reach senescence; they reproduce until they die.
Interestingly, a study of deer in west-central, northern, and east-central Illinois found that dominant females of any age produced more female offspring. Of fawns born to younger dominant females, 72% were female; to fawns born to older dominant or subordinate female breeders of any age, only 50% were female.
