Example of Baikal seal skull specimens. (a) Maxilla and (b) mandible tooth row. (c–f) Enlarged view of maxilla teeth. (c) Yellow arrows represent the number of cusps. (d) Yellow dashed line represents teeth–jaw junction, horizontal green arrow depicts tooth width, and vertical green arrow depicts tooth height. (e) Green line shows tooth perimeter. (f) Green line shows perimeter of the smallest bounding rectangle of the tooth. (g) Mandible tooth row, showing canine and 5 postcanine (PC1–PC5) teeth. (h) Green arrow shows gap length between PC3 and PC4. Credit: Ishihara U, Miyazaki N, Yurkowski DJ, Watanabe YY (2024) Multi-cusped postcanine teeth are associated with zooplankton feeding in phocid seals. Mar Ecol Prog Ser 729:233-245. 10.3354/meps14509