Spider’s Haemolymph can help improve robot’s hydraulic fluid based limb design

Unexpectedly, roboticist actually get ideas as they watch how spiders move or run. First robots do not use their joints as humans do, they actually fill up their joints with haemolymph to align it to be able to move. Haemolymph is a liquid substance or fluid equivalent to blood in most invertebrates.

Haemolymph is just like other fluids that tend to grow thick and sticky in consistency when there is a slight change or drop of temperature. This had made Nick Booster from Pitzer College to be curious about if spider’s movements are affected by temperature change.

If the question can then be answered, it would greatly contribute to the design of robots where hydraulic fluid is used to help move its limbs. Booster spoke to Anna Ahn and Steve Adolph and told them of his idea on his research to study the influence of temperature on spider movement as the two excitedly agreed to join in the study.

“I’ve always wanted to study spiders because they use hydraulics. This is a fascinating question. We wanted to understand how temperature affects the haemolymph and whether impaired haemolymph movement might influence the spiders’ ability to run,” Anna Ahn said .The team finally got to pick a Tesas brown tarantula where the spiders were tested as they performed all test over temperature control on the speed of the spider’s movement.

The results were indeed just as Ahn had suspected, the spiders moved as quickly at higher temperature while their movements tend to slow down at the lowest temperature.

Yet the faster they move the lesser they become synchronized with their movements not able to control their joints while when they move at a low temperature they are able to extend their third and fifth joints of their legs moving it simultaneously . Their study finally gave them the idea that the increase of viscosity in the haemolymph definitely controls the coordination of the spider’s movements.


‘Hydraulic extension may allow spiders to save space and mass in their limb, but it may come at the expense of control’, stated Ahn.



Leave a Reply

Your email address will not be published. Required fields are marked *