It most likely froze to death.................
Mambas are as calculating and deadly as Cottonmouths are psychotic and murderous. I worked with a Green Mamba at the Knoxville Zoo in the reptile display and was always cognizant of the danger when cleaning his area. No other dangerous snake made me as nervous as did a Mamba. Cottonmouths are just psychotic and strike with malice and carelessness. A Mamba is cold and very precise in its intentions.