Zebra black and white at birth. Plains and mountain zebra foals are protected by their mothers, as well as the head stallion and the other mares in their group. Grévy's zebra foals have only their mother as a regular protector, since, as noted above, Grévy's zebra groups often disband after a few months. Attempts have been made to train zebras for riding, since they have better resistance than horses to African diseases. While occasionally successful, most of these attempts failed due to the zebra's more unpredictable nature and tendency to panic under stress. For this reason, zebra-mules or zebroids (crosses between
GNU Zebra Infusion company and market a commercial version of Zebra, known as "ZebOS". This ZebOS is being used in networking products, such as FortiOS and the Citrix NetScaler. The official website states that "Zebra has been decommissioned". Since its last release (version 0.95) in 2005-09-08, development of Zebra appears to have stopped. A new project has emerged as the unofficial successor of Zebra: Quagga. Worldwide, many Linux/BSD based BGP-routers which were using Zebra are switching to Quagga. GNU Zebra Zebra is a routing software package that provides TCP/IP based routing services with routing protocols support such as RIP, OSPF and BGP.