European Souslik (Spermophylus citellus) head peering out of burrow amongst vegetation, Bulgaria

animals souslik eastern european east fields east europe east european vertebrate endotherm mammal developed country ground europe field eastern european head nature vertical mammalia burrow zoology sousliks developed countries european citellus verticals ground europe rodent fauna sousliks rodentia bulgaria mammal endothermic wildlife eastern europe bulgarian grasses warm blooded warm vertebrates squirrel sciuridae blooded mammals peering vegetation spermophylus animal grass animal