For crocodiles the GPS is recommended to be attached over the the nuchal shield area by either drilling the scales for a stainless steel wire to pass through, or having the stainless steel wire passing under the skin and below the largest scales. Surgery is necessary. 2 holes are included on the unit so the stainless steel wire can pass through. Diameter of the holes is defined by the customer, and in general weight is not the main concern, but the dimension to fit well. We can add water sensor so the unit will only turn on when it comes out of the water.
For turtles the GPS is recommended to be attached on the carapace usually glued, and in some particular cases holes are drilled to secure the unit. Turtles can carry up to 7% of their own weight though usually dimensions are of greater concern. For aquatic turtles we can add water sensor so the unit will only turn on when it comes out of the water.
Snakes are very tricky for a GPS unit because they can't be implanted and need the antenna(s) point towards the sky to work. We have made custom designs in which the unit is sewn over the snakes body, closer to the tail. Following we enlist some models but for snakes we need the customer to define shape, maximum weight and dimensions.
This list is intended for Lizard species of up to 250 grams considering they can carry a load of up to 5% of their own weight.