A method for identifying a composition for increasing palatability of a pet food product, comprising (a) contacting a test agent with a calcium-sensing receptor (CaSR) using in silico modeling, (b) detecting an in silico interaction between the test agent and one or more amino acids in a Venus Flytrap domain (VFT) or 7 transmembrane domain of the CaSR, and (c) selecting as the composition, a test agent that interacts with one or more of the amino acids, wherein the CaSR is selected from the group consisting of a feline CaSR comprising an amino acid sequence at least 85% identical to the amino acid sequence of SEQ ID NO:4 and a canine CaSR comprising an amino acid sequence at least 85% identical to the amino acid sequence of SEQ ID NO:5, wherein the one or more amino acids in the VFT are selected from the group consisting of ASN64, PHE65, ASN102, THR145, SER169, SER170, ASP190, GLN193, ASP216, TYR218, SER271, SER272, GLY273, GLU297, ALA298, TRP299, ALA300, SER301, SER302, LEU304, ALA321, TYR411, THR412, and HIS413; wherein the one or more amino acids in the 7TM are selected from the group consisting of ARG680; PHE684; GLY685; PHE688; VAL689 on Helix 3; GLN735 on Helix 4; ALA772; PHE775; LEU776; THR780; CYS781 on Helix 5; PHE814; VAL817; TRP818; PHE821 on Helix 6; GLU837; ALA840; ILE841; ALA844 on Helix 7; MET771 and GLU767 on EC2 loop; and wherein (i) an in vitro assay is performed to determine whether the test agent is a CaSR modulator, or (ii) palatability of a food product comprising the test agent is determined according to whether an animal demonstrates relative preference for the food product comprising the test agent over another food product. (a) contacting a test agent with a calcium-sensing receptor (CaSR) using in silico modeling, (b) detecting an in silico interaction between the test agent and one or more amino acids in a Venus Flytrap domain (VFT) or 7 transmembrane domain of the CaSR, and (c) selecting as the composition, a test agent that interacts with one or more of the amino acids, wherein the CaSR is selected from the group consisting of a feline CaSR comprising an amino acid sequence at least 85% identical to the amino acid sequence of SEQ ID NO:4 and a canine CaSR comprising an amino acid sequence at least 85% identical to the amino acid sequence of SEQ ID NO:5, wherein the one or more amino acids in the VFT are selected from the group consisting of ASN64, PHE65, ASN102, THR145, SER169, SER170, ASP190, GLN193, ASP216, TYR218, SER271, SER272, GLY273, GLU297, ALA298, TRP299, ALA300, SER301, SER302, LEU304, ALA321, TYR411, THR412, and HIS413; wherein the one or more amino acids in the 7TM are selected from the group consisting of ARG680; PHE684; GLY685; PHE688; VAL689 on Helix 3; GLN735 on Helix 4; ALA772; PHE775; LEU776; THR780; CYS781 on Helix 5; PHE814; VAL817; TRP818; PHE821 on Helix 6; GLU837; ALA840; ILE841; ALA844 on Helix 7; MET771 and GLU767 on EC2 loop; and wherein (i) an in vitro assay is performed to determine whether the test agent is a CaSR modulator, or (ii) palatability of a food product comprising the test agent is determined according to whether an animal demonstrates relative preference for the food product comprising the test agent over another food product. <EOS>