On this site, you can search for multimedia, specimens (collection specimens) and taxa (species descriptions of animals, plants, fungi), fossils, minerals and rocks.

The information will be supplied from the catalogues of Naturalis Biodiversity Center in Leiden, from the Nederlands Soortenregister and the Catalogue of Life.

On practically every specimen-page a PURL (Persistent Uniform Resource Locator) is present. You can cite the object described here by using this PURL. Naturalis will try to assure the permanent character of this PURL.

The BioPortal offers four possibilities for browsing this data:


Simple Search

Bioportal works in the same way as other well-known search engines: it uses your search terms to browse our sources. Within its search operations, it will examine all the fields specified in the advanced search (such as popular name, scientific name or discovery location) and will even browse fields not accessible via the advanced search.

Example: you can search for either [ brown rat ] or [ rattus norvegicus ].

If you type more than one search term, we will display all the results in which one, some or all of the terms occur, but we will head the list with results with the best match.

When you make a simple search the search term will be analysed and if there are more terms the search is divided into various parts. All these parts lead to potential search results and are combined with an OR, which can lead to very big search result sets.

It is not possible to use brackets or so-called wildcards. All foreign characters will be ignored in the query. To combine search terms, use the Advanced Search option.


Advanced Search

By clicking on the triangle symbol in the entry field, you will leave the simple search application, and start an advanced search. This means that you will limit your results to the category in which you are searching (multimedia, specimen or taxon) and to the specific fields in which you are searching.

If you enter search terms for more than one category, the result for each category will be shown.

If you enter more than one search field within a single category, initially, those results will be shown that include one or more of these terms.

If you opt to use ‘And’ for ‘Combine search terms’, the search engine will display results that contain all terms; in other words you will reduce the number of results.

Within the categories specimens and multimedia, you also have the option to restrict your search to a specific collection by selecting its name in the Collection name field. You can also limit your query for the categories Collection specimens, Taxa and Multimedia by selecting a specific Source (e.g. Botany or Zoology and Geology catalogues).


Geographic Search

You can use a geographic search to rapidly limit the number of search results to a particular area. The area can be selected from a list of areas on the right-hand side of the map, or drawn onto the map.

The results will always be limited to collection specimens and multimedia. Within this search type, only those results for which the geographical coordinates of the discovery location are stored in the source systems will be displayed.

We make use of a range of different sources. This means that in some cases, areas may be listed more than once. These areas will often differ in terms of degree of detail of the boundaries.


Explore Highlights

A simple and rapid search method is ‘Explore Highlights’. This search will result in a reproduction of all specimens that belong to one of the Special Collections at Naturalis. The results will be displayed immediately.

Search results

The aim of BioPortal is to deliver the results you are looking for quickly, and with that in mind, the system will use name resolution and ranking.

Name resolution

The BioPortal will attempt to match your search term to a scientific name. This will be achieved by browsing through various fields in the Nederlands Soortenregister and the Catalogue of Life.

1.    Scientific name
○     For example: “Rattus norvegicus”
2.    A list of popular names in various languages
○     One example is ‘Bruine Rat’ (Dutch) or “Brown Rat ” (English)
3.    Higher orders
○     For example “Rodentia” for the biological order rodents

This scientific name is then used to browse through multimedia and specimens. This may mean that your original query will not necessarily be literally reproduced in certain results.


The search results will be ranked according to

1.    Full match for the scientific name
2.    Full match for the species name
3.    Full match for the genus name
4.    Partial match for the scientific name
5.    Full match for any other field
6.    Partial match for any other field
7.    The number of times a matched is found/ The importance of a field


The search results are divided into four categories:

1.    Multimedia: pictures, sound or moving images from all data
2.    Taxa (species description)
3.    Specimens with the search term in the species name. Generates results if the search term occurs in the  taxonomical information of the specimen
4.    Specimens with the search term in another field. Generates results if the search term occurs in (for example) collection information, geographical information or information relating to time and dates. ‘Rat’ also generates results for ‘Rat Island in Plymouth, UK.

Specimens are references to and descriptions of objects stored in the Naturalis collection (and sometimes other collections). These descriptions can contain many different fields.