Yellowstone wolf pup survival hits record low amid distemper concerns

Yellowstone’s wolf pups had their worst survival year since wolves were reintroduced in 1995-96, and canine distemper is the leading suspected driver. Reporting from Wyoming and Yellowstone indicates that only 31 to 34 of at least 87 documented wolf pups survived in 2025 across the broader Wyoming population, while just 17 pups survived inside Yellowstone itself. Yellowstone had 108 wolves at the end of 2024, but by January 2026 the park reported at least 84 wolves. Wyoming wildlife officials said 64% of sampled wolves in the state’s northwestern trophy game area tested positive for distemper exposure or infection, well above a predicted baseline near 28%, and described the outbreak as “synchronous” with what was seen in Yellowstone. (nps.gov)

Why it matters: For veterinary professionals, this is a reminder that canine distemper remains a population-level threat in wild canids, not just an individual-animal disease in domestic practice. Yellowstone’s long-running wolf surveillance has shown that pup survival can collapse during distemper years, and earlier National Park Service and USGS work has linked past Yellowstone outbreaks to sharp pup losses while suggesting the virus likely persists through a broader multi-host carnivore community rather than wolves alone. That makes wildlife surveillance, domestic dog vaccination, and cross-species disease awareness especially relevant in and around shared landscapes. (nps.gov)

What to watch: Watch for Yellowstone’s 2025 annual wolf report and any updated Wyoming monitoring to clarify confirmed distemper testing, pup losses by pack, and whether survival rebounds in the 2026 denning season. (nps.gov)