In adders of the genus Bitis, the females have much shorter tails than the males – but without another tail to compare with, it could be confusing.

In the Boomslang (Dispholidus typus) in some parts of their distribution the males are usually green, but in the Cape provinces they are dark black-ish above with yellow, green or orange sides, whereas females are usually brown in colour. But it could be the other way around and juvenile Boomslang are greyish in colour, with big emerald eyes.

In some other snakes, males may have longer tails than females, but this is certainly not a universal rule.

To accurately establish the sex of a snake, a metal probe is inserted into the sexual organs towards the tail – in males the probe extends beyond 10 – 12 tail scales and in females less than 3.

The photograph below illustrates the tail length differences in the Puff Adder (Bitis arietans)