Integumentary glands of Columbian ground squirrels (Spermophilus columbianus): Sciuridae
The integumentary glands of Columbian ground squirrels (Spermophilus columbianus) were examined histologically. In addition to sebaceous glands associated with hair follicles, gland complexes were found in the oral angle, dorsal, and anal regions. The oral angle gland, located immediately posterior to the oral angle, was an apocrine-type gland consisting of three lobes each drained by a separate duct. Approximately 60 individual, oval-shaped glands, extending posterior from the scapular region, made up the dorsal gland field. These glands exhibited an apocrine secretory process and were drained by single ducts. The anal glands were located in retractable papillae near the anal aperture, one median ventral and two lateral. Equal portions of sebaceous and apocrine elements made up the anal glands. Sweat glands were found on the volar surface of the foot pads. Gland structure and location are discussed in relation to behavior patterns that appear to involve secretions from these glands. Possible functions of scent from these integumentary glands are considered briefly.