The two species cross paths in India and the Russian Far East.
Here are some quotes from relevant sources:
The wolf is a competitor of tiger everywhere. It is known that at places in the Primor'e where tigers live, wolves are absent or very few in number; it is thought that tigers destroy wolves (Kaplanov, 1948; G.F. Bromlei). From the diligence with which a tiger chases dogs, one may presume that it will hunt wolf just as tenaciously. -Mammals of the Soviet Union Vol. 2
Distribution and abundance of wolves follows an inverse pattern to tigers. Wolves were absent or exceedingly rare in the southern Russian Far East at the end of the 19th and beginning of the 20th centuries. Abramov (1940) believed that wolves appeared in the Sikhote-Alin only after the beginning of the 20th century, coincident with the abrupt range reduction of tigers… Wolf populations across the region decreased coincident with recovery of the tiger population since the 1940s. Today wolves are rare across the range of tigers, being found in scattered pockets, and usually as solo individuals or small groups… Although there are only four records of a tiger killing a wolf (Miquelle et al. 1996; Makovkin 1999), Amur tigers are notorious for killing dogs (Makarov and Tagirova 1989; Miquelle et al. in press); official records indicate 104 dogs killed by tigers in or near SAZ (where dogs are illegal) between 1957 and 2002. Tiger predation on another canid, the dhole (Cuon alpinus), has also been reported on several occasions (Venkataraman 1995; Karanth and Sunquist 2000). Although rarely observed, direct killing of one predator by another is suspected to play an important role in limiting many predator species (Palomares and Caro 1999; Woodroffe and Ginsberg, this volume). Thus, despite lack of clear evidence, we propose that direct killing of wolves by tigers has likely been an important element in reducing wolves to a functionally insignificant role in the Sikhote-Alin ecosystem. -Tigers and Wolves in the Russian Far East: Competitive Exclusion, Functional Redundancy, and Conservation Implications
Shown below is one of four wolves confirmed to have been killed and partially eaten by a tigress nicknamed Ilona in the Khingansky Reserve:
6 years as Animal Control Officer, Specialist on reptiles and exotics
Thanks for the request. Other than humans, it depends on where they live. Larger predators like bears and tigers have been listed. Badgers and wolverines also qualify. Basically any other large predator competing for survival. Even the bobcat.
works at University of Campinas
Although wolves are commonly classified as apex predators, they are susceptible of many parasites. According to google "Wolves are susceptible to more than one hundred diseases and parasites, including roundworm, tape worm, flatworm, mange, mites, ticks, fleas, distemper, cataracts, oral papillomatosis, tularemia, bovine tuberculosis, arthritis, cancer, rickets, pnumonia, Lyme disease, and many other ailments."
Original siteon Quora