It was narrated from Abdullah bin 'Amr that the Prophet (ﷺ) said:
"Killing by mistake that resembles intentionally, is killing with a whip or stick, for which the blood money is one hundred camels, of which forty should be pregnant she-camels in middle of their pregnancies, with their young in their wombs."
English reference: Vol. 3, Book 21, Hadith 2627
Arabic reference: Book 21, Hadith 2728