He is an adjunct professor of biology at UCSD and works for the Center for Reproduction of Endangered Species at the San Diego Zoo.
Ryder, who has published articles on mitochondrial DNA diversity in gorillas, also is the associate editor of the Journal of Heredity.
Dr. Joy Halverson, a canine DNA specialist with QuestGen Forensics in Davis, also testified.
A third man who took the stand declined to be identified.
Westerfield, 50, is charged with kidnapping, murder and misdemeanor possession of child pornography in the disappearance and killing of 7-year-old Danielle van Dam. The self-employed design engineer could get the death penalty if convicted of the felony charges.
Dogs have played crucial roles in the prosecution's case.
A volunteer handler testified last week that two search dogs "alerted" several times while sniffing in Westerfield's motor home four days after the victim was reported missing.
Jim Frazee, who helps the San Diego Sheriff's Department, said his dogs searched the 1997 Southwind motor home Feb. 6 at a vehicle storage facility on Aero Drive.
Also, police evidence technicians say hair consistent with Danielle van Dam's dog was found in the defendant's laundry.
Mudd has told defense attorney Steven Feldman to be ready to call his first witness Tuesday. Feldman has indicated he should be able to conclude his case by July 15.
Feldman told the judge he plans to call insect expert David Faulkner to the stand to try to pinpoint the time of Danielle's death.
In his opening statement, Feldman said the child's nude body could have been placed off a road in Dehesa as late as Feb. 16, a dozen days after his client came under 24-hour surveillance by law enforcement.
Prosecutors theorize that Westerfield, a twice-divorced father, killed the Sabre Springs second-grader and dumped her body at the East County site shortly after she disappeared Feb. 2. Volunteer searchers found the girl's decomposing body on Feb. 27.
Not closely focused on the case, that would be a real *critical* bit that I'm not aware the prosecution has been able to address. Someone correct me if I'm wrong.
Defendant David Westerfield sits in court as
witnesses testified about hair and carpet fiber
evidence, during proceedings June 24, 2002
at the San Diego courthouse. Westerfield is
accused of the kidnapping and murder of
seven-year old Danielle van Dam from her
Sabre Springs home, last February.
Photo by Pool/Reuters - Jun 24 8:38 PM ET
sw