The innovative structures called "utilitrees," seen behind the three elephants in the center left, provided shade; heat, in the form of radiant heaters hung at the top, out of the reach of the elephants' trunks; and options to hang browse, bales of hay and alfalfa, enrichment opportunities, and different types of food treats from the structure. Because they were not living trees, the utilitrees could not be destroyed, killed, or knocked down, preventing potential hazards and frequent and costly replacements. The pool was constructed with different levels and depths; some of the elephants mostly preferred to wade in the shallows, while others loved to completely submerge in the deep end, trunk held above the surface like a snorkel.