The wonderful Boomslang

My animal is the Boomslang snake, it lives in the African rainforest and preys on smaller mammals with its lethal hemotoxin. It can travel up to 4mph and is about 6ft long. in 2000 years, my animal will become semi acutic and develop a lethal combination of Neurotoxin and hemotoxin to kill faster. it will grow small legs to enable it to swim and run faster then before. It lives in the now, partially flooded African desert. it can change color to its surroundings and swim up to 5mph. it needs constant moustiure to keep its blood flowing . it preys on larger mammals and fish.