Provided are various embodiments relating to variant IgG Fc polypeptides of companion animals having increased Protein A binding for ease of purification, decreased C1q binding for reduced complement-mediated immune responses, decreased CD16 binding (e.g., for reduced antibody-dependent cellular cytotoxicity (ADCC) induction, increased stability, and/or the ability to form heterodimeric proteins. In addition, various embodiments relating to antibodies and fusion proteins comprising such variant IgG Fc polypeptides are provided. Also provided are various embodiments relating to contiguous polypeptides comprising one or more variant GLP1 polypeptide(s) having improved serum half-life. Further provided are various embodiments relating to contiguous polypeptides or heterodimeric polypeptides comprising a GLP1 polypeptide and a glucagon polypeptide as a dual GLP1 receptor and glucagon receptor agonist. In various embodiments, such polypeptides may be used to treat, for example, diabetes, obesity, or related indications, in companion animals, such as canines, felines, and equines.
