1895.] MYODES LEMMUS. 47 

and OC. lagopus; Mustela erminea and M. mivalis; amongst birds 
Nyctea scandiaca and Asio acewpitrinus, Nyctala tengmalmi, Sur- 
nia funerea, as well as the (somewhat scarcer) Syrmum aluco 
and S. uralense; of ordinary birds of prey, all the Falcons, especi- 
ally Falco tinmunculus, likewise Archibuteo lagopus, and even 
Aquila chrysattos. 
To these may be added å number of irregular enemies which 
it is mainly of physiological interest to indicate. 
Both the wild and tame reindeer occasionally persecute the 
lemmings*. They first kill them with their fore hoofs and horns, 
and subsequently devour them bodily. The cows and goats in 
the mountain regions occasionally do the same (but no similar 
observations have been made in respect to sheep). That pigs 
eat them whenever they have å chance is no anomaly. 
This apparent anomaly may, however, be physiologically 
explained. The ,desire for salt felt by all ruminants arises 
from the want of soda salts in their ordinary vegetable food, 
and it is this crave they endeavour to assuage, by occasionally 
devouring animal food which contains more of these salts. 
We likewise may mention Stercorarius parasttteus (S. buffoni) 
as one which, almost solely in these years in which Myodes ap- 
pear in multidudes, breeds on the southern mountains of Norway. 
This is also the case with Circus cyaneus; this species broods 
but sparingly on the plateaux of the mountains in the south, 
but has not been proved to breed with us except during these 
migratory years of the lemming”. 
1 This is especially observable in the tame Reindeer during å lemming 
year. *No matter how well broken in and quiet åa Reindeer may 
be, it will, nevertheless, at once turn aside on scenting a lemming, 
and seize it (if it can). The head is first eaten; some discard the 
remainder, whilst others consume both head and body. Before 
deep snow fell that winter (1871 —72) the Lapps, on account of the 
lemmings, found it difficult to keep their herds together, and they 
said that the cause of the Reindeer being so thin that season, was 
due to their continual chase of the Lemming.” (Boström, Jågerförb. 
nya tidskrift, 1872, p. 101. Stockh. 1872.) 
? Nyt Mag. f. Naturv. B. 35, p. 177, (Christiania 1893—94). 
