Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to care for newborn hamsters [title] Assess the parents' risk factors. [step] Hamsters reach sexual maturity as young as 6 weeks old, though it is not advisable to let them mate at this age. A female should be at least 8-10 weeks old before mating, and males 10-12 weeks old.

Ending1: If they are older, reduce the amount of activity and expectations (sex to avoid unwanted pregnancy) during this age. These factors can range from poor appearance to poor behavior. Ending2: [substeps] The mother will have the easier time mating if she has more feces or is nursing, especially at this age. [title] Consider the mother's inclination to mate. Ending3: Once a hamster reaches 12 months of age, it should no longer be bred, as health risks skyrocket. [substeps] The average hamster lifespan is 18-24 months. Ending4: However, this is less important for everyone who plans to breed a single hamster. [title] Pick a cage that fits your hamsters' species.

Answer format: ending1/ending2/ending3/ending4