 Tortoises sometimes rest in mud wallows or rain @-@ formed pools , which may be both a thermoregulatory response during cool nights , and a protection from parasites such as mosquitoes and ticks . Parasites are countered by taking dust baths in loose soil . Some tortoises have been noted to shelter at night under overhanging rocks . - others have been observed sleeping in a snug depression in the earth or brush called a " pallet " . Local tortoises using the same pallet sites , such as on Volcán Alcedo , results in the formation of small , sandy pits . 
