Congenital Tracheal Web Malformation in a Wild Brown Bear ( Ursus arctos ), Sweden, 2010.

We describe a congenital tracheal web malformation in a wild female brown bear (Ursus arctos) yearling that was euthanized after being hit by a train in Norrbotten County, Sweden, December 2010. A 3-cm-long, abnormal, longitudinal mucosal fold divided the trachea into two halves, without obviously blocking the airflow.

Fallot's tetralogy in a European brown bear (Ursus arctos).

A congenital heart malformation was diagnosed in a free-ranging adult female European brown bear (Ursus arctos) found dead due to intraspecific violence. At necropsy, the heart had all four features of Fallot's tetralogy. No further malformations were identified in the animal, which was of normal size and weight for its age, in normal body condition, and had probably borne young. The heart condition was considered to have contributed to death during an attack by another bear.

Hypospadias in a polar bear (Ursus maritimus).

Corrective surgery on a 1.5-yr-old male polar bear (Ursus maritimus) with hypospadias included amputation of the vestigial penis, bilateral orchiectomy with scrotal ablation, and distal perineal urethrostomy. Hypospadias in other species is a congenital deformity that may be caused by extra- and intrauterine factors resulting in a disruption of the testosterone balance during urethral development, but the causative mechanism in this bear is unknown. The urethrostomy site was functional without complications 8 mo after surgery.

Female pseudohermaphrodite polar bears at Svalbard.

During research on polar bears (Ursus maritimus) at Svalbard in April 1996, we captured two yearlings with a normal vaginal opening and a 20 mm penis containing a baculum. The penis was located caudal to the location in a normal male and was concealed within the vaginal opening by a single pair of labia. The urethral opening was situated laterally about 5 mm from the distal end of the penis. Neither of the yearlings showed signs of a Y chromosome, so both bears were regarded as female pseudohermaphrodites. On separate occasions in two bears, we recorded aberrant genitalia morphology with a high degree of clitoral hypertrophy in Svalbard, which we also classified as female pseudohermaphroditism. The observed rate of female pseudohermaphroditism in this area was 1.5% (4/269). Pseudohermaphroditism in this polar bear population could result from excessive androgen excretion by the mother caused by a tumor, or it could be a result of endocrine disruption from environmental pollutants.

Agenesis of a radius in a polar bear cub (Ursus maritimus).

A polar bear (Ursus maritimus) cub, delivered by a cesarean section, was diagnosed with congenital agenesis of the radius on the basis of clinical presentation and radiology. A specific etiology could not be ascertained. Agenesis of the radius has not been previously reported in any nondomestic species.