Sources:

https://www.merriam-webster.com/dictionary/instinct

http://www.zo.utexas.edu/courses/Thoc/HumanInstincts.html

https://exploringyourmind.com/the-abcs-of-human-instincts/

https://onlinelibrary.wiley.com/doi/abs/10.1002/9781118663219.wbegss301

http://teacher.scholastic.com/activities/explorations/bats/libraryarticle.asp?ItemID=224&SubjectID=111&categoryID=3&SubjectName=Birds

https://psychology.wikia.org/wiki/Instinctive_behavior