April 15: edit
- 1790 - Theobald Jones was born in Kilcronaghan, Northern Ireland.
- 1801 - Édouard Lartet was born in Castelnau-Barbarens, France.
- 1857 - John Mason Clarke was born in Canandaigua, New York, USA.
- 1883 - Vladimir Kovalevsky died in Moscow, Russian Empire.
- 1907 - Eduard Meine van Zinderen-Bakker was born in Opsterland, Netherlands.
- 1964 - Alice Wilson died in Ottawa, Ontario, Canada at age 82.
- 2015 - William L. Parsons and Kristen M. Parsons studied ontogenetic variations in Deinonychus antirrhopus and suggested that young members of the species may have been able to fly.