Report Abuse. You should get them at 8 weeks old. That's an age where it won't be dramatic for them to be without their mother (or at least a caregiver that can take care of them 24/7) and old enough where you can start training. A lot of rescue center won't even give dogs younger than that.Silvia Â· 5 years ago. Thumbs up.eport Abuse. You should get them at 8 weeks old. That's an age where it won't be dramatic for them to be without their mother (or at least a caregiver that can take care of them 24/7) and old enough where you can start training. A lot of rescue center won't even give dogs younger than that. Silvia Â· 5 years ago.
Updated August 04, 2014. You can use a black light to detect body fluids. It's actually a good way to look for pet urine or make sure a bathroom or hotel room is really clean. Cat urine, in particular, glows very brightly under ultraviolet light. Urine glows under a black light primarily because it contains the element phosphorus.
A black light is a source of electromagnetic radiation that emits near-ultraviolet light, usually in the 350-375 nanometer wavelength range. This range is just slightly below the 400nm that human eyes can detect. When this light is reflected off certain materials, it looses energy and its wavelength expands to over 400nm. The reflected light is then visible to human eyes, and the illuminated objects appear to glow.