Mammoths have been found that had eaten tropical vegetation

Claim

How come theorists never mention that the majority of mammoths that we find…[have]…tropical vegetation still in their teeth and digestive tracks?

Rebuttal

1. The best preserved mammoth, Lyuba, was indeed found with frozen vegetation in her digestive tract. However it was all from plants found in northern environments, not the tropics.
   1. Her stomach mostly contains branches from 9 species of moss (Polytrichum, Abietinella abietina, Tomentypnumnitens, Calliergon richardsonii, Hylocomium splendens, Aulacomnium turgidum, Drepano cladus  and Sphagnum) which are currently “widely spread from the Arctic tundra to southern taiga“.
   2. 4 species of other plants (Festuca, Carex, Ranunculus flammula  and Ranunculus acer) were also found and again they are all northern species which “are common for both the tundra and boreal zones”

References

Kosintsev, P. A., E. G. Lapteva, S. S. Trofimova, O. G. Zanina, A. N. Tikhonov, and J. Plicht. 2010. ‘The Intestinal Contents of a Baby Woolly Mammoth (Mammuthus Primigenius Blumenbach, 1799) from the Yuribey River (Yamal Peninsula)’. Doklady Biological Sciences 432(1): 209–211.