Several "tracked" jeep prototypes were built, because of such a need in Alaska and Canada. After America had entered the war, a Japanese attack on the Aleutians made the Alaskan military base there suddenly a zone of great military importance. The snow-rich circumstances created a need for tracked, jeep-like, all-purpose vehicles, and the Canadian Bombardier company created the T29 jeep half-track out of one of the existing 6−6 Willys MT chassis. Due to Willys' workload, International Harvester helped assemble a further five T29E1 prototypes. Under the steering front wheels, skis could also be mounted. An Aberdeen test report critiqued that the T-29E1 was difficult to steer, as the tracks could not be controlled independently, and that prolonged use caused excessive track component wear. The only known surviving half-track WWII jeep is named WillysT28 'Penguin'. Further (fully) tracked "jeeps" were also armored, and developed for, and by Canada — "see section 'Armored jeeps.