Alcetaurs are similar to centaurs but with the body of a moose. They are extremely proficient with the bow. They're said to be less trustworthy than centaurs. They're never more at home than when out in the wilderness.
According to Henrick, Alcetaurs are solitary by nature, as opposed to Cervitaurs (men with bodies of deer) and Rumitaurs (men with bodies of elk) although Henrick was with his mother well into his adulthood until she suggested he find purpose at Wyrmroost, where he became the sanctuary's Gamekeeper.
In the Fablehaven series
An Alcetaur was one of the sentries at front gate in Blackwell Keep.
In the Dragonwatch series
The alcetaur is formally introduced as Henrick, the Gamekeeper of Wyrmroost.