The sheer size of the coconut crabâ€”it is the world's largest known terrestrial arthropodâ€”as well as its coconut-cracking pincers make this hermit crab an intimidating creature. Unlike most hermit crabs, coconut crabs cannot swim. Instead of gills, they possess a special organ called a branchiostegal lung, which is suited to absorb oxygen from air rather than water but must be kept moist if it is to function. Why is the coconut crab sometimes called the "robber crab" or "palm thief"?
Back in the day
Frederick Barbarossa was elected King of Germany in 1152 and crowned Holy Roman Emperor in 1155. Shortly thereafter, an apparent misunderstanding with Pope Adrian IV led Frederick to mount military operations against Italy and install an antipope in opposition to Adrian's successor. The schism continued for some time, but Frederick and the Catholic pontiff ultimately reconciled. According to scholars, what factors may have contributed to Frederick's drowning death in the shallow Saleph River?
Born on a day like today
Henry the Navigator, a Portuguese prince, figured strongly in Portugal's early development as a colonial empire. Though not a navigator himself, Henry was a great patron of exploration and is credited with establishing a school for navigators and encouraging the study of navigational instruments and cartography. Under his patronage, Portuguese sailors explored and colonized Madeira, the Cape Verde Islands, and the Azores. How did Henry justify Portugal's involvement in the African slave trade?