A new type of spines from woody species informs on major historical mammal food stress events and suggests mammal bark feeding as a vegetation driver of past ecosystems.

Plant spines are known to defend leaves against mammals, nevertheless, the presence of woody species harbouring spines on their trunk where none of the common plant edible parts are established raise the question of the trunk spine function and their ecological significance. The present work indicated that trunk spines may defend against mammal bark feeding and that it could have played an important role in influencing past vegetation establishment, especially in sub-tropical and tropical dry seasonal vegetation. Furthermore, it suggested that major earth events such as climate switches may have induced important mammal food stress events increasing consequently the consumption of fallback bark resource by mammals and their effect on vegetation structure and composition. The present work concluded that fallback resource may have played a major role in influencing mammal and plant community ecology and evolution in bottleneck conditions.