Specimen of the Week 277: Hornbill Skull
By Dean W Veall, on 3 February 2017
Hello Specimen of the Week fans, Dean Veall here. This week I’ve chosen a specimen that is a bit of an avian showoff in the animal world (**PLUG PLUG**Join us on Thursday 9 March for more showoffs in Animal Showoff **PLUG PLUG**). That is no mean feat for birds, a group of vertebrates that are known for their showoffy-ness. My Specimen of Week is a hornbill skull and I fear I cannot restrain myself from singing the one song hornbills are famous for. Can’t place the song? Read on…..
**Black-casqued hornbill (Ceratogymna atrata) **
Hornbills are a group of bird consisting of around 54 different species, with around 23 species found on the savannahs and forests of Africa and 31 species living in the tropical rain forests of Asia. The group is categorised by their distinctive bill which is long, down-curved and usually brightly colored and can reach lengths of 13 inches. The largest hornbill is the rhinoceros hornbill which is roughly the size of a swan with a wingspan of nearly a metre which according to the Iban people of Borneo represents the god of war. If I were to choose a favourite species I would go for southern ground hornbill (Bucorvus leadbeateri) due to it’s pretty fierce eyelashes and also they look pretty fierce in general; one should not mess with this bird.
A feature that is unique to all hornbills is the structure than runs along the top of the bill known as the casque which serves primarily as a reinforcing ridge along the bill. In many species it is hollow and has been modified as a resonator to amplify the bird’s calls, possibly playing a part in sexual selection. In some species it is barely noticeable and appears to have no function beyond reinforcing the bill. Whilst in one species, the helmeted hornbill (Buceros vigil) it is completely solid and is referred to as hornbill ‘ivory’, which is more valuable that true ivory.
This specimen of the week has been a bit of mystery for some of Team Grant, the casque of this specimen had a weird honeycomb structure that was generally atypical. So my colleague Jack took to social media and discovered that the specimen was over-prepared by boiling and therefore it was not actually pathological as previously suspected.
Hornbills are generally monogamous with many mating for life. Once they have a mate, hornbills nest in tree cavities which are sealed shut except for a narrow vertical slit. No big deal, except the female is sealed inside?!?! The slit is about half an inch wide, just wide enough for the male to pass food through but too narrow for predators to try and get inside. It’s a two-way exchange with food coming in and poo going out. The enclosed female will shoot out her excrement as far as possible from the nest by putting her rear end over the slit, by doing so she not only keeps a clean nest but also prevents predators locating the nest by the faecal smell.
And here we are, that aforementioned song by everyone’s favourite hornbill (red billed, Tockus sp. in case you were wondering) from the hit 1994 Disney film The Lion King.
Dean Veall is Learning and Access Officer at the Grant Museum of Zoology