A joint tenancy is an estate held by two or more persons jointly so that during the lives of all they are equally entitled to the enjoyment of the land. Upon the death of one, his share vests in the survivor or survivors until there is but one survivor, when the estate becomes one in severalty in him. There may be a joint tenancy in fee, for life, or for years. A joint tenancy can only be created by purchase; it cannot be acquired by descent.

In the creation of a joint tenancy, four unities must be present, viz.; interest, title, time and possession. One tenant cannot hold for life and another in fee or one by one deed and another under a will. The estate of all must vest at the same time in order that there may be unity of time. One tenant cannot hold in possession and another in reversion or remainder. Joint tenants, thus, must have one and the same interest arising from one and the same conveyance, commencing at one and the same time, and held by one and the same possession. Another incident of joint tenancy is the peculiar doctrine of survivorship.

Survivorship is the doctrine whereby the interest of a joint tenant upon his death falls to the survivor or survivors among the joint tenants.

A joint tenancy and the right of survivorship, however, may be destroyed by a conveyance by one joint tenant to a stranger. Such stranger at once becomes a tenant in common and the alienation thus destroys the survivorship. If there be more than two joint tenants the conveyance by one of his share will not affect the right of survivorship among the others, who are still joint tenants as to each other.

Formerly a joint estate was presumed to be a joint tenancy unless the contrary clearly appeared. At the present time however the law does not favor joint tenancies and every joint estate is held to be a tenancy in common, unless the instrument creating the estate expressly declares that the tenants shall hold in joint tenancy.