It might be thorny, but it does not need to be thirsty. This is thanks to “their microstructured skin surface, with channels in between overlapping scales, [that] enables them to collect water by capillarity and passively transport it to the mouth for ingestion”.
Read more from the article.
Comanns et al. (2017) “Adsorption and movement of water by skin of the Australian thorny devil (Agamidae: Moloch horridus)” https://doi.org/10.1098/rsos.170591 available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5627102/