Sunday, February 7, 2010

Harp Seal Necropsy


This Friday, a recently thawed beater harp seal (Phoca groenlandica) was necropsied by me and a team of students and Allied Whale employees. The seal was hit by a car in its head, shattering large parts of its mandible, skull and maxilla. The force of the impact caused the seal to defecate (feces were found around the perianal region, although death was probably (and hopefully) instant. Fur from its front flippers was missing, suggesting that the beater had crawled for some time before reaching the road. Besides the cranial damage, the rest of the seal seemed to be in good shape. Concavity of the pelvic region suggested that the seal was slightly thin, but not emaciated. The presence of a penile opening clearly identified the seal as a male.

The necropsy began by removing the integument, Amanda Dunn and Michelle Klein accompanying me. The front flippers were then removed, but not before I spotted the prescapular lymph node (which I suppose I was overly excited to find). Amanda took the right and I took the left. We opened up the abdominal cavity next. A green fluid (bile?) was found inside the mesentery around the large intestines, but the intestines overall looked healthy. The kidneys were remarkably reniculated, and one showed damage in the form of lacerations (source unknown).

The thoracic cavity was then opened, and I am sad to say I failed at finding the sweet spot (mid articulations of the ribs), mostly likely due to the positioning of the carcass slightly on the right. The lungs were thoroughly soaked in blood, most likely post-mortem. The heart appeared fine, and the aorta was characteristically a pale beige. Due to the chaos of trying to remove the rib cage, I overlooked finding the diaphragm. We incised the trachea, which appeared healthy, and removed the head from the body. The extent of damage to the head was profound. Bits of skull and maxilla were resting on the tongue, and the skin of the head easily slid off the bone. The brain was clearly impacted from the force of the bones snapping back dorsally, and the teeth were sunken into the gums.

After we disposed of the carcass, everyone scrubbed-out and went home. Most of the blood had been drained before the necropsy began, both in the bag it was held in and at the accident site, so this was probably one of the cleanest necropsy's I will ever witness. I was grateful to have a code 2 body to work with, and even more appreciative of the help I received. Thank you to Spencer, Leah, Rosie, Jessica, Michelle, Amanda and especially to Jackie for helping out! Below are some pictures (courtesy of Ms. Klein)





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