92 NATURE'S STORY OF THE YEAR 



or to be resisted. And so natural is it to the fish 

 to " draw " these little swords, that if some strange 

 living object has to be removed from the vicinity 

 of the nest, the spines will be erected when it 

 is seized, as though another fish were being 



THE MALE THREE-SPINED STICKLEBACK AT HIS NEST. 



attacked. And they are extended when the fish 

 gapes or wriggles in a way that suggests " stretch- 

 ing itself." And they also serve to indicate 

 thought in the fish, for when one meditates an 

 attack on a neighbour, you can see the spines 

 twitch, and sometimes, when he thinks better of it 



