Hepatocellular tumors are overrepresented in humans, woodchucks (Marmot monax), Richardson’s ground squirrels (Urocitellus richardsonii), black-tailed prairie dogs (Cynomys ludovicianus), and meerkats (Suricata suricatta).The tumors are associated with hepadnavirus infection in humans, woodchucks and ground squirrels, and the woodchuck is an animal model for human hepatitis B. A review of the archives at Northwest ZooPath identified 54 Fennec fox (FF) submissions, of which 15 (28%) (9.4.2) had 1 or more types of proliferative hepatocellular lesions, including hyperplasia (9), adenoma (8) and carcinoma (8). Of the remaining 147 archived foxes representing 12 other species, only a single hepatocellular adenoma was identified. Average age at diagnosis was 10.3 yrs (range=8–13 yrs). One adenoma and one carcinoma had trabecular and pelioid patterns, and all others were trabecular. Metastasis (omentum and lymph node) was seen in one case. Zoo listserve solicitation identified several more cases. Prospective and retrospective serologic and metagenomic studies are being conducted on serum from affected animals and unaffected cohorts, and on frozen tissues or paraffin blocks, for exposure to potentially oncogenic infectious agents.