Cocoa Standard, Cocoa Satin, Chocolate Standard, and Chocolate Satin 13-day-old kitten rats. Rats owned and bred by Karen Robbins, Karen’s Kritters. Photo ©1997 Craig Robbins.

Cocoa Satin vs Cocoa Standard 13-day-old kitten rats. Rats owned and bred by Karen Robbins, Karen’s Kritters. Photo ©1997 Craig Robbins.

Chocolate Satin vs Chocolate Standard 13-day-old kitten rats with 2 Cocoas in the background. Rats owned and bred by Karen Robbins, Karen’s Kritters. Photo ©1997 Craig Robbins.

Cocoa vs. Chocolate 4-week-old kitten rats. Rats owned and bred by Karen Robbins, Karen’s Kritters. Photo ©1996 Craig Robbins.

Cocoa vs. Chocolate 4-week-old kitten rats. Rats owned and bred by Karen Robbins, Karen’s Kritters. Photo ©1996 Craig Robbins.

Cocoa 4-week-old kitten rat drinking water. Rat owned and bred by Karen Robbins, Karen’s Kritters. Photo ©1996 Craig Robbins.

Cocoa 4-week-old kitten rat. Rat owned and bred by Karen Robbins, Karen’s Kritters. Photo ©1996 Craig Robbins.

A 4-month-old Cocoa male rat. Rat owned and bred by Karen Robbins, Karen’s Kritters. Photo ©1999 Craig Robbins.

A 4-month-old molting dark Cocoa male rat. Rat owned and bred by Karen Robbins, Karen’s Kritters. Photo ©2000 Craig Robbins.