The introduction of living invertebrates into the classroom was investigated. First, possible anchor points for a lesson with living invertebrates are explored by referring to the curriculum of primary/secondary schools and to out-of-school learning. The effectiveness of living animals for increasing interest, motivation, and achievement in recent research is discussed. Next, the Vivarium, an out-of-school learning facility with living invertebrates, is described. The effects of an intervention study with living invertebrates on achievement are then investigated at school (School condition) and out of school (University condition); a third group served as a control condition. The sample consisted of 1861 students (an age range of 10–12 years). Invertebrate-inspired achievement was measured as pre-, post-, and follow-up-tests. Measures of trait and state motivation were applied. The nested data structure was treated with three-level analyses. While achievement generally increased in the treatment groups as compared to the control group, there were significant differences by treatment. The University condition was more effective than the School condition. Achievement was positively related to conscientiousness/interest and negatively to tension. The study concludes that out-of-school learning offers achievement gains when compared to the same treatment implemented at school. The outlook focuses on further research questions that could be implemented with the Vivarium.