Number of animals used for experiments in 2023

The German Center for the Protection of Laboratory Animals (Bf3R), which is part of the Federal Institute for Risk Assessment (BfR), has published the animal testing figures for 2023 (1). After the Federal Ministry of Food and Agriculture (BMEL) had had this function for years, it was taken over by the BfR in 2021. Since then, the records not only show the number of animals used in experiments or killed for organ harvesting, but also list those animals that were bred but not used in actual experiments and were therefore killed as “surplus”. The statistics reveal that a total of 3,501,693 animals were used or killed. Despite a decrease compared to the previous year, Doctors Against Animal Experiments (DAAE) considers this figure to be alarming and sees it as confirmation of its strong demand for a paradigm shift from animal experiments to human-relevant research methods.

Total number of animals

The total number of laboratory animals officially published by the BMEL and BfR (2023: 1,456,562) has, for several years, referred solely to animals that were actually used in experiments. This creates the impression of a significant decline compared to previous years, when animals 'killed for scientific purposes' were also included in the statistics. As a result, it becomes considerably more difficult to directly compare the numbers over time.

Moreover, the definitions of what is considered the 'total number' vary significantly: While Doctors Against Animal Experiments and other animal protection organizations include all animals that suffer and die for experiments — amounting to a total of 3,501,693 animals — the exclusion of surplus animals and animals killed for scientific purposes results in a lower and seemingly less alarming figure.

Purpose	Animals in 2023
Used in animal experiments (Animal Protection Act, Art. 7)	1,456,562
...thereof first use	1,424,848
...thereof re-use	31,714
Killed for scientific purposes (e.g. organ harvesting)	671,958
Animal experiments + killed for scientific purposes	2,128,520
'Surplus animals': animals killed for other reasons (e.g. undesirable genetic modification, too old, wrong sex, etc.)	1,373,173
Total	3,501,693

Table 1: Overview of the total number of animals used in animal experiments.

Development of the animal numbers

Since data collection began in 1989, the number of animals has fallen from 2.6 million to a minimum of 1.5 million in 1997, followed by a continuous increase to 2.8 million in 2011. Since then, the number has remained at a similarly high level with slight fluctuations. Since 2020, however, a slight decline has become apparent, which has become more pronounced in the past two years. This trend is primarily due to a comparatively significant reduction in the number of so-called surplus animals, whose numbers were abruptly cut by almost half. It is questionable how such a drastic reduction could be achieved in such a short period. Moreover, this development raises the fundamental question of how seriously the issue of surplus animals was addressed in the past.

Species used in animal experiments

As in previous years, mice are by far the most frequently used animal species in experiments with 1,062,632 individuals (73%). In second place are fish with 161,713 animals (11.1 %), followed by rats with 102,731. In addition, rabbits (67,524), birds (20,521), pigs (9,643), guinea pigs (7,863), dogs (2,550), monkeys (1,676), cats (544) and other animal species continue to be used.

The figures refer to ‘animals used in animal experiments’.

Experiments on non-human primates

The number of monkeys used in experiments fell from 2,267 in 2022 to 1,676 in 2023. However, the Bf3R uses figures from 2018 as a reference, when the number of monkeys used peaked at 3,324. This suggests a decrease of 49%, which distorts the actual development. The figures are subject to considerable fluctuations, particularly in this area, and a clear downward trend is not evident in the long term.

187 of the 1,676 monkeys used in 2023 were re-used from the previous year. Among non-human primates, the proportion of animals used multiple times is comparatively high at 11%.

Of the monkeys used in experiments for the first time, 1,318 came from non-EU countries, in particular from countries in Asia or Africa. By comparison, only 171 animals were obtained from registered breeders within the EU.

The majority of the monkeys (1,493) were used for regulatory purposes such as toxicity tests. Most of the monkeys in Germany are used by the company ‘Lapcorp’ (formerly Covance) (2).

Basic research is the largest consumer of animals

It is particularly striking that the number of animals used for basic research, which by definition has no purpose and must suffer or die in the process, has remained at a consistently high level for years. These animal experiments have accounted for more than half of all animal experiments for years, and this figure has risen once again.

In 1999, 438,000 animals were used in basic research, four years later there were already around twice as many animals (851,000 animals). In 2016, basic research reached its highest level to date with 1,175,664 animals.

From 2017 to 2022, animals ‘killed for scientific purposes’ were not included in the official statistics, which makes it difficult to compare the figures before and after these years. In 2023, however, a detailed breakdown of animals ‘killed for scientific purposes’ was provided. This includes animals that are killed for tissue or organ removal. 615,246 of these animals (91.6%) were used in basic research.

According to the current figures for 2023, 852,209 animals were used directly in experiments as part of basic research, which corresponds to a share of 58.5% and represents an increase of 3% compared to the previous year. In absolute terms, however, the number of animals used in basic research fell by almost 105,000.

The figures given by the Bf3R only refer to animals used directly in experiments.

Regulatory animal testing on the decline

Unfortunately, the hoped-for downward trend in the area of regulatory animal testing did not continue: After a share of 15.8% in 2022, this rose in 2023 to 16.9%.

For comparison: in 2018, the proportion of animal experiments in this area was 484,254 animals (22.6%). It fell to 272,452 animals (15.8%) in the following years up to 2022.

On a positive note, the absolute number of animals used in this area fell from 272,452 in 2022 to 246,650 in 2023.

The legally required tests include procedures such as drug tests for humans and animals as well as tests for medical products, biocides, pesticides and also food and animal feed.

The long-term downward trend in this area is due to the growing number of available animal-free methods. These are methods that do not involve live animals, e.g. organ-on-chip systems, cell cultures, and computer-based models. This also includes clinical and epidemiological research. Such modern research methods should be increasingly promoted. In contrast to animal testing, non-animal test systems offer reliable results that can be transferred to humans.

The figures given by the Bf3R in this area relate only to animals used directly in experiments.

The number of genetically modified animals continues to grow

In 2023, 738,066 animals were genetically modified, which corresponds to a share of 50.6 %. The most frequently genetically modified animals are mice, fish and rats. Little has changed here compared to the previous year, but in 2011 the proportion was only 25%.

Although the number of genetically modified animals in 2023 (738,066) is lower than in the previous year (918,276), the actual number is significantly higher, as these statistics only take into account animals used in animal experiments. Many of the so-called surplus animals, which are also genetically manipulated, are now included in a separate breakdown for the first time. A total of 1,070,422 genetically modified animals, mainly mice and fish, were killed as surplus, which accounts for 78% of all surplus animals.

The figures for ‘animals killed for scientific purposes’ with genetic modification are now also broken down in detail: organs or tissue were removed for scientific purposes from 380,986 animals that were genetically manipulated.

50,741 animals endured 'severe' suffering

With a percentage share of 3.5%, the proportion of animal experiments in the ‘severe’ severity category remains almost the same compared to the previous year. In absolute terms, however, the number has fallen from 62,377 (2022) to 50,741 (2023). Nevertheless, it must be taken into account that over 50,000 animals continued to experience severe suffering in 2023.

Experiments with mild distress account for 63.8% (previous year 66.3%), and experiments with moderate distress for 27.5% (previous year 25.4%). Experiments involving ‘non-recovery’ accounted for 5.3% in 2023 (previous year 4.7%). The latter means that the experiment is designed to kill the animals under anaesthesia, for example.

With the revision of the EU Animal Experiments Directive, the severity levels to which the animals are exposed have been recorded since 2014. It should be noted that the classification of severity levels is carried out by the researchers themselves - i.e. the people who have the greatest interest in these experiments being approved. A DAAE study showed that the severity levels are often understated.

Hidden animal suffering

There has been a fundamental change in the animal testing figures since 2021: animals that were bred in laboratories for scientific purposes but not used for these purposes and therefore killed as so-called surplus animals are also recorded. In 2023, 1,373,173 Tiere (2022: 1,769,437) animals were killed for lack of intended use, mostly for purely economic reasons.

Animals assigned to this area are, for example, animals that have been genetically modified but do not carry the desired genetic modification - and are therefore worthless for researchers. As there is no use for them in the laboratories, they are killed. It is also possible that animals don’t have the desired age or sex for the planned experiments and therefore become worthless for research.

The figures have another significant weakness in terms of transparency: All the animals that die in breeding facilities, during transport to the laboratory or before entering or after completion of an experimental project are not so-called surplus animals and are therefore not yet included in any statistics (4).

There is a further gap in the statistics for invertebrates. Apart from cephalopods (squid, octopuses), invertebrates such as insects and crustaceans are not counted at all. In 2023, 70 cephalopods were used, in 2022, the number was 56.

Trend of animal experimentation figures since 1989

Figure 2: The graph shows the number of animals used in animal experiments and killed for scientific purposes. 

Last updated: 12.12.2024